Basilica Cistern in Istanbul — FAQ

What is the Basilica Cistern?
The Basilica Cistern is a vast 6th-century underground reservoir built by the Byzantines, with 336 columns rising from the water, dramatic lighting and two famous Medusa-head column bases.
Should I book Basilica Cistern tickets in advance?
Yes — the cistern is very popular with long queues; skip-the-line tickets save time, especially in peak season, and an evening visit is atmospheric.
Why are there Medusa heads in the cistern?
Two columns rest on ancient Medusa-head bases, reused from older Roman structures and placed sideways and upside-down; their origin is uncertain, adding to the cistern’s mystery.