Basilica Cistern

In the very heart of Istanbul, a two-minute walk from the majestic Hagia Sophia, beneath the noisy streets of the Sultanahmet district, lies one of the most astonishing and atmospheric structures of the Byzantine Empire — the Basilica Cistern. Locals call it Yerebatan Sarnıcı, which means "Sunken Palace." And this name perfectly conveys the impression that everyone descending underground experiences.