Istiqlal Mosque (1978) is the largest mosque in Southeast Asia (it can accommodate 20 000 worshippers). It has contemporary lines and a minimalist interior, with 12 aluminium-plated columns and a gridwork of windows allowing the light to flood in. There are passageways leading to the four floors of the immense prayer hall. Inside you should also take time to admire the calligraphy at the base of the dome, which is 2.5m high and 136m long.