The Philadelphia 76ers have experienced the zenith of basketball three times throughout their history, with two of those championships coming in Philly after the move from Syracuse in 1963. The Sixers' last title, however, came nearly four decades ago. As one of the original franchises in the NBA, the Sixers have a rich history of high moments. However, Philadelphia has also gone through some rough times and suffered through some of the most gut-wrenching experiences as a fan base.

Here are some of the most heartbreaking moments in Philadelphia 76ers history.

Allen Iverson's tenure with 76ers comes to a close

To this day, Allen Iverson is still one of the most beloved players in the City of Brotherly Love. However, his tenure with the Sixers didn't end on particularly good terms.

Iverson spent 10 seasons in Philadelphia. He experienced everything with the Sixers, from high points such as winning MVP and reaching the NBA Finals in 2001, to a fair share of low points. However, in the 2006-07 season, his tenure with the Sixers was about to turn to its lowest.

Turmoil began to brew between the former league MVP and the front office. Iverson sent an ultimatum to management: make the team better or trade me. On Dec. 19, 2006, Philly fans saw the Sixers trade Iverson to the Denver Nuggets.

It was definitely a tough pill to swallow for fans who adored Iverson for everything he gave for Philadelphia. In his first interview after the trade, Iverson told ESPN's Stephen A. Smith he felt relieved that the trade finally went through. While he expressed his love for Philly fans, he also admitted how tough it was to play as a superstar for the Sixers:

While the post-Iverson Sixers did make the playoffs for a couple of seasons, they never really regained the same kind of relevance they had when they had The Answer as the face of the franchise.

Dr. J's final game

Julius Erving announced his retirement on opening night of the 1986-87 season. Dr. J's final season was filled with tributes from all over the league, including from his rivals, the Boston Celtics and Los Angeles Lakers.

Philadelphia struggled through an injury-plagued campaign but still managed to make the playoffs as the fifth seed. The Sixers faced the Milwaukee Bucks in the first round and split the first four games. In the deciding Game 5, Philadelphia found itself getting blown out by Milwaukee. It became clearer that as the clock ticked down to its final minutes, this would be the final dance of Julius Erving's illustrious career.

Erving still continued to fight with the Sixers trailing by double digits. Finally, with 40 seconds remaining, Dr. J checked out of the game for the final time as the Milwaukee fans gave him a standing ovation. This was certainly an emotional sight for Sixers fans, who never got to witness the NBA legend's final game in person.

Kawhi Leonard's shot heard around the world

Let's start by reopening a wound, shall we? The apology is sent in advance on this one if you're a 76ers fan.

The Sixers and Toronto Raptors went back and forth through the first six games of the Eastern Conference Semifinals in 2019. The series was ticketed and came down to a deciding Game 7 in Toronto. Much like most of the series, Game 7 saw a tight contest between the two East rivals and went down to the wire until the very final possession.

Both teams were deadlocked at 90 apiece with 4.2 seconds remaining. The Raptors had possession and had the opportunity to erase the dark memories of 2001 when Vince Carter failed to send Toronto to the Eastern Conference Finals with a last-second game-winner. This set the stage for a dramatic finish and one that nobody who witnessed it will ever forget.

As expected, Kawhi Leonard was the choice for Toronto to work through on the final possession. Kawhi received the ball near the logo. The Raptors superstar then dribbled to the end of the baseline and launched a fadeaway shot over the outstretched arms of Joel Embiid. As time expired, the ball bounced around the rim four times before all hell broke loose.

Kevin Harlan and Greg Anthony just screamed in disbelief as Leonard's shot finally fell into the net. Series over. Embiid cried on the way to the locker room, and soon enough, the memes all over social media started rolling in. The loss haunts him to this day.

The Raptors advanced to the Eastern Conference Finals and eventually won their first NBA championship. Philadelphia, meanwhile, lost a number of key pieces such as Jimmy Butler and JJ Redick in the offseason after going all-in with legitimate title aspirations during that year.

Every Sixers fan still wishes that the replay shows Leonard's shot bouncing out instead of falling in:

Such a brutal moment for Sixers fans and an NBA playoff moment that will go down in the history books.

So, what do you make of this list consisting of the most heartbreaking moments in 76ers history?