Mentioned by Lonely Planet
20 best free things to do in London
"Located in what was once Bankside Power Station on the south bank of the Thames, Tate Modern is one of the city's most loved attractions. You can enjoy the permanent collection, which includes works by Pollock, Warhol, Matisse and Picasso, for free. The 10th-floor viewing deck of the Blavatnik Building offers wonderful panoramic views over the Thames and beyond, and the building itself is amazing."