Basilica Cistern, Underground cistern in Istanbul, Turkey
The Basilica Cistern is the largest of several hundred ancient cisterns that lie beneath the city of Istanbul.
Built in the 6th century during the reign of Byzantine Emperor Justinian I, this cathedral-sized cistern is an important piece of Istanbul's historic fabric.
Featured in many works of literature and film, the Basilica Cistern represents a mysterious and romantic side of Istanbul.
Today, it is open to the public as a museum with a wooden walkway for easy access to visitors.
The cistern houses two stone Medusa heads used as column bases, with no clear explanation as to why they were placed there.
Location: Fatih
Architectural style: Byzantine architecture
Website: yerebatan.com/homepage
Source: Wikimedia