In the first half of 18th century, water supply system was built in Prabuty that provide residents easy access to good water. This water was to come from the nearby Lake Mlynskie, to the market it flew through a hundred-meter length of the channel. This channel, having reached the market branched leading to some underground tanks located in the corners of the market. These tanks are about 4 meters in diameter and over 5 meters of height. The water is extracted to the surface by means of manual pumps. This system worked smoothly later to be replaced with modern waterworks. Lake Mlynskie was dried in 19th century, and the channels with the market tanks have not been used since then. You can explore them, although they are accessible to tourists only in July and August. Exploration should be agreed in advance with the local tourist information. Some conservation work the underground system is planned in the nearest future, equipping it with lighting and making it the city attraction open to all visitors. For now the underground exploration of Prabuty should be treated as an easy type of cave tourism and prepare for it, supplying a good flashlight.
The underground route in Prabuty is one of regional attractions that are just waiting for the full release. Even today, it is worth to keep in mind this rare urban oddity, and list it in the sightseeing program for the Vistula part of Gdańsk Pomerania.