In one of the more bizaare episodes of the series, time is all messed up. Its 2011 and there's Pterodactyl, flying dinosaurs flying over London. There's a Roman Charioteer on the streets and Sir Winston Churchill is still in charge of the country. Time is stuck and won't move.
The Doctor has a beard and is dressed like a Roman nobleman. The Doctor is talking with Churchill but is interrupted by special forces personnel led by Amy Pond. Amy is wearing an eye patch and isn't married to Rory Williams. Amy takes the Doctor back to her headquarters which is a large Pyramid.
Inside the Pyramid are The Silence behind glass panels in cell like areas. In the middle of the centre is Madame Kovarian, the woman who had kidnapped Amy Pond earlier and taken her child who would later grow up to be River Song.
River Song is in the room when the Silence break free from their glass prisons and attack the place. Rory wants to hold them off but Amy has other ideas as the group retreat to the top of the Pyramid. According to the Doctor, time will return back to normal when river Song and the Doctor marry with Amy and Rory as witnesses.
Once the marriage has occurred, time reverts back to normal. We see what really happen at the river in Utah at the beginning of the season (The Impossible Astronaut). It wasn't the Doctor but an android copy with the Doctor inside controlling the machine. It was the same sort of robots that appeared in Lets Kill Hitler