Hallgrímskirkja, Iceland

Reykjavík’s immense white-concrete church (1945–86), star of a thousand postcards, dominates the skyline and is visible from up to 20km away. An elevator trip up the 74.5m-high tower reveals an unmissable view of the city. In contrast to the high drama outside, the Lutheran church’s interior is quite plain. The most eye-catching feature is the vast 5275-pipe organ installed in 1992. The church’s size and radical design caused controversy, and its architect, Guðjón Samúelsson (1887–1950), never saw its completion.