What makes a great Finals series? Tension, drama, momentum shifts -- and not just from game to game, but from quarter to quarter or even moment to moment. A great NBA Finals series goes sometimes six games, but more often than not the greatest are grueling seven-game duels that leave both the winners and the losers drained. NBA.com sifted through the history books and highlights to compile an unofficial list of the Greatest Series in Finals History. Read these and also check out the Greatest Finals Moments and Greatest Finals Performances, as well as the All-Time Finals Challenge, which was won by the 1986-87 Lakers.

15. (Tie) 1978: Washington Bullets 4, Seattle Sonics 3
Led by Wes Unseld and Elvin Hayes, the Bullets knew something about fighting back. Down 3-1 in the Eastern Conference Finals to the San Antonio Spurs, the Bullets won three straight, storming to The Finals to meet the Sonics. Washington then trailed 3-2 to Seattle, but as Coach Dick Motta famously proclaimed: "The opera ain't over until the fat lady sings." The Bullets stormed back with a 117-82 Game 6 win at home, and then went to Seattle and became the third team to win a Game 7 on the road (following the 1969 and 1974 Celtics).

The first time the Bullets and the Sonics met in the NBA Finals, they created a classic.
(Walter Iooss Jr./NBAE/Getty Images)

15. (Tie) 1951: Rochester Royals 4, New York Knicks 3
The Royals, who finished second to the Minneapolis Lakers in the West Division, found themselves in The Finals against the New York Knicks. It appeared the NBA would have its first Finals sweep in its short history, but the Knicks had other ideas. They won the next three games to force a Game 7 in Rochester. The Royals avoided the indignity of blowing a 3-0 series lead with a 79-75 win for the title. To this day, the Knicks are the only team in NBA history to force a Game 7 after going down 3-0.

14. 1974: Boston Celtics 4, Milwaukee Bucks 3
This Finals series was one of the most interesting in NBA history. The teams alternated wins throughout the series, with Boston taking the first game in Milwaukee. And after the Celtics beat the Bucks in Game 3 to take a 2-1 series lead, the home team never won another game. In the classic Game 6, John Havlicek hit a basket to send the game into OT, another to send the game in double-OT and a shot to give the Celtics a one-point lead with six seconds remaining in the second overtime. The Bucks countered with a Kareem skyhook and headed back to Milwaukee tied at 3-3. The Celtics would continue the series' trend of winning on the road, clinching the title in Milwaukee.

13. 1987: Los Angeles Lakers 4, Boston Celtics 2
Recently a panel of experts on NBA.com named the 1987 Lakers the winners of the All-Time Finals Challenge, a tournament featuring the NBA's greatest teams. In the 1987 Finals, they defeated the defending NBA champs, the 1986 Celtics, who finished as runners-up in the Challenge. The Lakers easily took the first two games in LA, but then lost Game 3 in Boston Garden. It looked as if they would lose Game 4 as well until Magic Johnson came to the rescue. Magic beat Kevin McHale off the dribble on the wing and headed into the lane where he launched a baby skyhook over McHale and Robert Parish's outstretched arms. The shot gave the Lakers Game 4, a 3-1 series lead and the momentum to take the series.

12. 1980: Los Angeles Lakers 4, Philadelphia 76ers 2
Every basketball fan knew of Magic Johnson from his days as an NCAA champion with Michigan State. But no one had any premonition as to what Magic was going to do in Game 6. With that season's MVP, Kareem Abdul-Jabbar, out with an ankle sprain, the rookie point guard started at center. And a legend was born as Johnson scored 42 points, grabbed 15 rebounds and dished seven assists to clinch the series in Philly.

11. 1966: Boston Celtics 4, Los Angeles Lakers 3
The Lakers started the series so well, winning Game 1 133-129 in overtime in Boston Garden. For the next three games, the Lakers went downhill, losing all three, including two in Los Angeles. Down 3-1, they had to head back to Boston. Series over, right? Wrong, the Lakers won the next two to force a Game 7 in Boston. The Lakers, who had never beaten the Celtics in three previous Finals series, would go to 0-4 as Boston won the last of its record eight consecutive titles with a 95-93 victory in Red Auerbach's final game as a coach.

10. 1993: Chicago Bulls 4, Phoenix Suns 2
Though it only went six games, this series had enough thrills for two Finals. The series headed back to Chicago as Bulls stole the first two games in Phoenix, and it looked as if the Suns were about to set. But in Game 3, the Suns pulled out a 129-121 win in a classic 3OT contest. The Suns again looked done after losing Game 4, but prevented the Bulls and their fans a chance to celebrate by winning Game 5 at Chicago Stadium. Late into Game 6, it appeared that the Suns would force a Game 7 in Phoenix as they had a 98-96 lead with time running out. But Bulls guard John Paxson drained a game-winning three from the left wing to give Chicago its third consecutive title.

Because of Jordan, many of the Finals series in which he played were great.
(Jonathan Daniel/NBAE/Getty Images)

9. 1988: Los Angeles Lakers 4, Detroit Pistons 3
The Lakers were making their seventh appearance in The Finals during the '80s when they faced the Detroit Pistons, who hadn't been to The Finals since the franchise was in Ft. Wayne, Ind. But Detroit started strong with a Game 1 win in L.A. By the time the horn sounded in Game 5, it looked as if the Pistons were the Finals-tested team as the series headed west with them holding a 3-2 lead. And then came the monumental Game 6, where Isiah Thomas severely sprained his ankle yet still scored a Finals-record 25 points in the third quarter. Still, the Lakers eked out a 103-102 win. The Lakers then became the first team in 19 years to win back-to-back titles as they topped the Pistons 108-105 in Game 7.

8. 1977: Portland Trail Blazers 4, Philadelphia 76ers 2
Before their appearance in the 1977 Finals, the Blazers had never even made the playoffs in their previous six seasons. On the other side, after a great career in the ABA, Julius Erving was making his first Finals appearance. After winning the first two games, it appeared as if Erving and the Sixers would make quite a first Finals impression. But in Portland, the series took a dramatic turn as the Blazers dusted the Sixers by an average of 26 points. The series returned to Philly, but the moment stayed with Portland, which stole Game 5, 110-104. By this time, Blazermania was in full frenzy. The Blazers took their only title to date with a 109-107 win in Game 6.

7. 1985: Los Angeles Lakers 4, Boston Celtics 2
By the time the 38-year-old Kareem Abdul-Jabbar took the floor in the 1985 Finals, he had done everything there was to be done in basketball. He owned six MVP trophies. He was the NBA's all-time leading scorer. He had won three NBA titles. But neither he nor the Lakers had ever beaten the Boston Celtics for a championship. After the Memorial Day Massacre -- a 148-114 Game 1 loss in Boston Garden -- it seemed that it would end like the eight previous Finals meetings between the franchises -- with a Celtics championship. But history took a vacation for this series, as Kareem would be named MVP as he led the Lakers past the Celtics in six games. The clinching game marked the only time the C's were eliminated from The Finals at Boston Garden.

6. 1997: Chicago Bulls 4, Utah Jazz 2
Though only six games, this series featured three game-winning shots in the waning moments. And the Bulls hit all three. It began with Jordan hitting a game-winner in the series opener. The series was tied at 2-2 after Utah won Game 4 in part due to a remarkable full-court assist from John Stockton to Karl Malone in the late moments. The Jazz were primed to become the first team to win three consecutive games at home in the 2-3-2 format when it was announced that Michael Jordan had the flu and was questionable for Game 5. By the end of that game, the only question asked was: "How did he do that?" Jordan scored 38 points and nailed the game-clinching 3-pointer. The series shifted back to Chicago for Game 6 where Steve Kerr turned out to be the hero when he nailed a 20-footer assisted by, who else, Jordan.

5. 1957: Boston Celtics 4, St. Louis Hawks 3
If this series had taken place in today's media-saturated environment, we might be calling it the greatest ever. It opened with St. Louis beating the Celtics in Boston Garden 125-123 in double-OT. It ended in Game 7 with St. Louis losing to the Celtics in Boston Garden 125-123 in double overtime. Each of the Hawks' three wins were by two points. With the exception of Game 7, the Celtics never won by less than five points. In the most incredible seventh game in NBA Finals history, Boston rookies Bill Russell and Tom Heinsohn combined for 55 points and 56 rebounds as the Celtics won their first title.

4. 1962: Boston Celtics 4, Los Angeles Lakers 3
When it came to heartbreak in The Finals, no team knew the pain of losing more than the Los Angeles Lakers. In the first of six Finals meetings between these two teams in the 1960s, the Lakers appeared as if they would win the series in L.A. as they took a 3-2 series lead back to the West Coast. But the Celtics' Finals experience proved to be invaluable as they clobbered the Lakers 119-105 in Game 6. Two days later, the Celtics took the fourth of their eight straight titles with a thrilling 110-107 win in overtime, after L.A.'s Frank Selvy missed a baseline shot which would have won the series in regulation.

Bird and Magic met three times in the NBA Finals and it was their first meeting, 1984, that's the greatest ever.
(Andrew D. Bernstein/NBAE/Getty Images)

3. 1969: Boston Celtics 4, Los Angeles Lakers 3
In their sixth and final Finals meeting of the decade, the Celtics again trumped the Lakers. The Celtics' dynasty was on its last legs and the Lakers had acquired Wilt Chamberlain before the season for the sole purpose of dethroning the Celtics.

Jerry West scored 53 to lead L.A. to a 120-118 win in Game 1. Then ten-time champion Sam Jones tied the series at 2 for Boston with a Game 4 buzzer-beater.

Heading into Game 7, the Lakers had prepared to drop balloons from the rafters of The Forum after their expected win. But with a 108-106 win, the Celtics kept the balloons from falling, thanks to tenacious play, a Chamberlain injury and a fortuitous bounce off a Don Nelson shot. Bill Russell retired with perhaps the most satisfying, and certainly the most improbable, of his 11 championship rings, while Jerry West was named the only Finals MVP from a losing team after posting 42 points, 13 rebounds and 12 assists in Game 7.

2. 1970: New York Knicks 4, Los Angeles Lakers 3
The Lakers were making their seventh Finals appearance since 1962. The Knicks were making their first since 1953. This series featured back-to-back overtime games in Games 3 and 4, with the teams splitting. In Game 3, Dave DeBusschere appeared to win the game on a jumper with three seconds left, but Jerry West countered with a 60-footer, forcing the Knicks to work overtime to prevail.

New York would win Game 5 in stunning fashion, executing a remarkable comeback with a small lineup after Willis Reed tore his thigh early in the game. In Game 6, the Lakers tore through the Knicks to win by 23 and tie the series at 3-3.

Though the series headed back to New York for Game 7, Reed was questionable. But about 10 minutes before tipoff, Reed hobbled out of the Knicks locker room and into NBA history. Reed didn't play much, but he hit his first two shots and gave the Knicks -- and the Madison Square Garden crowd -- a much-needed psychological boost. Knicks guard Walt Frazier led New York to its first title with 36 points and 19 assists.

1. 1984: Boston Celtics 4, Los Angeles Lakers 3
This was the seventh Finals meetings between Boston and the L.A. Lakers, the first since 1969, and it ended the same way the previous six did. This Finals had everything and it has been the standard bearer for Finals series before or since. It featured the first Finals matchup between Larry Bird and Magic Johnson. It had Gerald Henderson's dramatic steal of a James Worthy pass to force overtime in Game 2, which led to Boston's imperative salvaging of one win in two home games.

"To be honest, if it wasn't for that steal, we probably would have been swept," said Bird.

You had Bird calling his teammates "sissies" after getting chewed up and spit out by 33 in Game 3. There were the Celtics fighting back in Game 4 for another overtime win. With the Celtics having home-court advantage in what was now a three-game series, the teams traded home wins. The Celtics won in a Boston Garden sauna in Game 5 with Bird scoring 34 on 15-20 shooting. L.A. rallied at The Forum behind 30 from Kareem Abdul-Jabbar in Game 6. And in Game 7, the Celtics used a team effort -- led by 24 points, eight rebounds and eight assists from Cedric Maxwell -- to score a 111-102 win for the 15th title in franchise history and seventh over the Lakers.