Lionel Messi, one of the greatest football players of all time, has stunned Barcelona by telling the club he wants to leave. 

The Argentina superstar has spent his entire career at the Catalan giants, but now looks likely to start the 2020-21 campaign with a new club. 

Where Messi goes remains to be seen but any deal for the 33-year-old will rank as one of the most dramatic in the history of sport. 

Here, we look at a selection of other sporting deals that shocked the world. 

Neymar: Barcelona to Paris Saint-Germain, 2017

The Brazilian had formed a potent attacking trio with Messi and Luis Suarez at Camp Nou but a move to PSG was inevitable when the French side met his world-record buyout clause of €222million. He has played an important role in their continued dominance of domestic football, but has so far been unable to guide them to Champions League glory. He was reduced to tears by his side's 1-0 defeat to Bayern Munich in the 2020 final last week. 

LeBron James: Cleveland Cavaliers to Miami Heat, 2010

Basketball icon James announced that he would sign with the Miami Heat instead of returning to his hometown team, the Cleveland Cavaliers. Then a two-time NBA Most Valuable Player and a six-time All-Star, James added to the spectacle of the stunning move by announcing it on a special television broadcast called The Decision. He enjoyed four years in Miami, where he won a pair of NBA titles, before returning to the Cavaliers in 2014. 

Tom Brady: New England Patriots to Tampa Bay Buccaneers, 2020

Few people expected Brady to leave the Patriots after 20 years and six Super Bowl victories. Not only did one of the game's greatest ever quarterbacks leave, but he joined one of the least successful franchises in NFL history. Time will tell if his decision to sign with a highly promising Buccaneers team proves to be a masterstroke. 

Luis Figo: Barcelona to Real Madrid, 2000

Should Messi ever return to Camp Nou as an opposition player it is unlikely he will be on the receiving end of the kind of abuse that greeted Figo. Barca fans threw bottles, lighters and even a pig's head at the Portuguese star when he went back to Camp Nou with Los Blancos in the seasons following his controversial move. 

Wayne Gretzky: Edmonton Oilers to Los Angeles Kings, 1988

In 1988, the Edmonton Oilers and Los Angeles Kings agreed a deal that shook the NHL to its core. The trade left Canada in disbelief, with a member of the country's parliament even proposing the federal government block the trade or buy Gretzky's contract and sell it to another Canadian team. "The Great One" would go on to enjoy eight successful years in Los Angeles before spells with St. Louis Blues and New York Rangers.