Lake Voulismeni is a freshwater lake in the town of Agios Nikolaos. This is one of two freshwater lakes of the island of Crete. Lake Voulismeni is located in the city centre and is a well-known local landmark. The inhabitants of the city called "the lake". It is circular with a diameter of 137 m and depth 64 m. the Lake Voulismeni is connected with the sea by a canal, which was dug 1867-1870, then surface water become salty, but at depths below 30 m of the lake remains of freshwater. Along the canal today is the city port.

The lake has always been shrouded in legends. Long time local residents thought that the lake is bottomless. Considered this place to be inhabited by evil spirits that caused the emergence of various superstitions. This myth was dispelled in 1853, when the British Admiral Spratt measured the depth in the center of the lake, it was 210 feet (64 m). Also, according to legend, the lake bathed the goddess Athena and Artemis.

The lake has a distinctive vertical walls that resemble volcanic crater. So for a while it was believed that the lake was formed in place of a sunken volcano. To date there is no evidence. In 1956, during the eruption of Santorini volcano, the water came from the banks of the lake, it is possible to assume that there is a geological fault that connects Voulismeni and Santorini. This assumption is also not yet received the evidence.

At the end of the Second World War, when the German army left the island, locals flooded in the lake all the weapons and armored vehicles, as a symbol of liberation from the invaders.

Renowned sea researcher Jacques-Yves Cousteau visited the town of Agios Nikolaos specifically for the study lakes.

Every year on the eve of the feast of the Passover most of the population of the city is going at midnight near lake Voulismeni and host a Grand celebration with fireworks.

The Western part of the lake is surrounded by cliffs and its Eastern side is occupied numerous restaurants and cafes that offer a beautiful panoramic view. Lake Voulismeni is the center of night life of the city.