The Basilica Cistern is one of the largest and most impressive ancient
underground cisterns still open to visitors. However, it is not officially
recognised as the largest underground cistern in the world.
A more accurate description is that the Basilica Cistern is the largest
surviving Byzantine underground cistern in Istanbul. Its enormous interior,
hundreds of marble columns and historical water system make it one of the
city’s most remarkable structures. You can learn more about its development
in the
history of the Basilica Cistern
.
How Large Is the Basilica Cistern?
The Basilica Cistern measures approximately 138 metres long and 65 metres
wide. It covers an area of nearly 10,000 square metres.
Inside, there are 336 marble columns arranged in 12 rows. Each row contains
28 columns. Most of the columns are about nine metres high and support the
brick-vaulted ceiling above them. Their materials, capitals and arrangement
are explained in the guide to the
columns of the Basilica Cistern
.
The cistern could once store approximately 80,000 cubic metres of water.
This water was supplied through aqueducts and used by the imperial buildings
in Constantinople.
Why Was Such a Large Cistern Built?
The Basilica Cistern was constructed during the reign of Byzantine Emperor
Justinian I in the 6th century. Its main purpose was to provide water for
the Great Palace and nearby public buildings.
Large underground reservoirs were important because Constantinople sometimes
faced water shortages and sieges. Storing water below the city helped protect
the supply from weather conditions, contamination and outside attacks.
The cistern formed part of a much wider network of aqueducts, channels and
reservoirs. More details can be found in the guide to the
Byzantine water supply system
.
Its design was practical rather than decorative. Many columns and stone
elements were reused from older Roman buildings, which explains their
different styles and materials. The arches, brick vaults and underground
structure are covered in more detail in the
Basilica Cistern architecture guide
.
How Does It Compare with Other Istanbul Cisterns?
Istanbul contains many underground cisterns dating from the Byzantine period.
The Basilica Cistern is the largest surviving covered cistern that visitors
can enter in the city today.
The Binbirdirek Cistern is another major underground structure, but it is
smaller than the Basilica Cistern. The Theodosius Cistern is also smaller
and contains only 32 columns. These sites are compared in the guide to the
most popular cisterns in Istanbul
.
There were larger open-air water reservoirs in Byzantine Constantinople.
However, these structures were not fully underground and did not have the
same forest-like arrangement of columns.
Why Is It Called the Sunken Palace?
The Turkish name of the Basilica Cistern is Yerebatan Sarnıcı,
which can be translated as the “Sunken Cistern.” It is also commonly called
the “Sunken Palace.”
This nickname comes from its grand appearance. The long rows of illuminated
columns, vaulted ceiling and reflections on the shallow water make the
interior look more like an underground palace than a water reservoir.
The Basilica Cistern may not be the world’s largest underground cistern, but
it remains one of the most impressive examples of Byzantine engineering.
Its scale, history and unusual atmosphere continue to make it a major
attraction in Istanbul.
Visitors who want to see the underground structure with expert commentary
can check the
Basilica Cistern guided tour with an entry ticket
.