Saint Sava Temple

The dome mosaic is forty million pieces of gold and glass — and it only went up in 2020, after eighty years of bare concrete.

Outside, white marble under a 4,000-tonne dome that was assembled on the ground in 1989 and lifted into place in one piece. Inside it is a single vast room with no columns, and underneath it a crypt church covered in frescoes in a completely different, warmer register.

Why it's worth it

Few buildings anywhere let you see a medieval Byzantine form executed with twentieth-century engineering.

Insider

Most people walk in, look up and leave — go down to the crypt instead: nine colours of marble, different acoustics, and almost nobody there.

• gold mosaic
• the crypt
• free entry