The Art Fund Prize for Museum of the Year 2015 will be awarded on 1 July.
The prize celebrates the best museums and galleries across the UK.
BBC News visited each museum on the shortlist.
Used since 1078 as a fortress, palace and prison, the Tower of London is now one of London's most popular tourist attractions.
In 2014 something new attracted over five million visitors - a work of art commemorating the centenary of World War One consisting of 888,246 individual ceramic poppies.
The exhibit became one defining images of the centenary events.
Video Journalist: James Dowd & Matt Margrett
Extra footage courtesy of Historic Royal Palaces
Find out about the other museums and galleries nominated for the Art Fund Prize for Museum of the Year 2015
The BBC in partnership with The Art Fund
