'The Sunken Palace' is the biggest of the hundreds of underground reservoirs underneath the streets of Istanbul, dating from Byzantine Constantinople.
If you'd like a change from the bazaars, palaces and mosques of the typical Istanbul visit, then the Basilica Cistern offers something very different. Known as the Yerebatan Sarayi in Turkish, it is the most celebrated of the many reservoirs built in Byzantine times, and the most impressive. It's also an excellent place to cool down during a hot summer's day.
Dating from the 6th century and the rule of Emperor Justinian, it was built to provide water for the Great Palace. Over time, it was forgotten and became a dumping ground for local people, until found once again in the 16th century, when it was restored to its former majesty and used to provide water for the Topkapi Palace.
Follow the raised walkways – installed in the 1990s – around 'The Sunken Palace' to best appreciate this enormous structure. The experience is further heightened by the atmospheric lighting and music, perfectly setting the ambience of this subterranean wonder. Keep a sharp lookout for the ancient Medusa heads, which can be found at the back, on the north-western side.
As a feat of engineering, it is hugely impressive. Containing 336 marble columns, and covering almost 1 hectare, the Basilica Cistern held over 80 million litres of water during its heyday, which were sent far and wide through 19 kilometres of aqueducts. When we consider that this was designed and constructed around 1,500 years ago, without the benefits of modern techniques or of the technology we possess today, the scale of this achievement becomes even more astounding.
A visit takes less than one hour, and there is a cafe selling snacks, soft drinks and wonderful Turkish-style tea at the site. The Basilica Cistern is open every day, and there is an entrance fee for foreigners. You can reach it from the nearby Atram stop.