Sagrada Família, Barcelona

Antoni Gaudí's extraordinary basilica, under construction since 1882 and due to be finished in the coming years. Its towers rise like sandcastles over Barcelona, and the interior is a forest of branching stone columns lit by stained glass in glowing colours. Gaudí is buried in the crypt.

Tickets are timed and sell out, so book online well ahead; a tower visit by lift is extra. Go in the morning for blue and green light through the east windows, or late afternoon for the warm reds and oranges.