Frost fair
The frost fair was a celebration held on the surface of the River Thames when it froze over. Carnival festivities, shows, games, ice skating, shopping, and other celebratory events were held on the open surface of the ice.
The Second Doctor, Jamie McCrimmon, Ben Jackson, and Polly Wright visited the frost fair in 1648. (PDA: The Roundheads)
The First Doctor, Steven Taylor, and Vicki Pallister visited the frost fair in 1814. (CC: Frostfire) An unspecified Doctor, River Song and Stevie Wonder visited the same fair for River's birthday, where Stevie performed for them, in private, under one of the bridges. This was described as the last frost fair. (DW: A Good Man Goes to War)