Basilica Cistern, located near the Hagia Sophia Museum, is one of the most charming buildings in all of Istanbul. This place is considered a large underground water reservoir, which has a storage capacity of 100,000 tons of water. By visiting the Basilica Cistern in Istanbul from the inside, you can enjoy the wonderful and amazing Byzantine sculpture through dozens of huge columns designed and carved with precision, art and mastery, numbering approximately 336 columns, two of which are in the form of Medusa heads, according to legend, which is one of the Greek myths It was used to protect this great building. You can also enjoy seeing wonderful groups of different colors of fish swimming under your feet in a reasonable level of water. Basilica Cistern houses a wonderful café serving refreshing drinks and delicious snacks either after or during the visit.