In recent years, the Mint has issued several series of coins with special reverses. Most of them have been 25¢ coins, particularly in the years 1999–2001. There were also versions of the $2 coin commemorating the founding of Nunavut, and another with a family of polar bears; there have been several variants of the $1 coin, one of which featured the Canadian peacekeepers' monument in Ottawa to commemorate the award of the Nobel Peace Prize. A commemorative Terry Fox $1 coin began circulating on April 4, 2005.