The second Monday of March marks Commonwealth Day, a holiday celebrated in the United Kingdom and its sovereign territories. Festivities often include patriotic events such as flag-raising and reading the Commonwealth message from the reigning monarch.

The Commonwealth is a global family of 54 member countries, from Canada and Great Britain to New Zealand, South Africa, Nigeria, India and Tuvalu. The modern Commonwealth, which represent a quarter of all humanity, evolved out of Britain's imperial past. Today, it helps to advance democracy, human rights, and sustainable economic and social development.

Commonwealth Day is celebrated during a multi-faith service in Westminster Abbey attended by the reigning monarch and other members of the Royal Family, the Commonwealth Secretary-General and the Commonwealth High Commissioners in London.