Concorde was grounded after the first and only accident in its entire career. A piece of metal came off a poorly maintained US DC-10 on take-off, and when Concorde used the runway it flipped up and into the fuel tank. The plane's engine exploded and it landed on a building killing all on board.
This was the first and only accident in Concorde's entire operational history. It remains one of the safest aircraft ever built.
Conspiracy theorists had a field day. Just as the US tried to ban the Concorde at birth, they said, now they have succeeded in killing them. The problem with that view is that the British Airways Concordes continued flying for some months afterwards, before being grounded. However it appears a mix of operational cost and business knowledge - letting Virgin buy them would have been to hand a huge business advantage to a rival - did more to eventually ground Concorde than any conspiracy.
No matter what may be said about certain political lobbies - rarely the friends of aviation - the US aviation fans loved her. This video shows her last departure from JFK and the radio transmissions between the tower and BA Concorde Speedbird 2. It is not often an ATC Tower admits "We're gonna miss you."