The water reservoir on the Yellow Hill in Brno is a unique technical monument hidden under the surface of the city. This large underground complex was built in the 1870s as part of the city's water supply system and was used to store and distribute drinking water. It is made up of several monumental brick tanks with vaulted ceilings that have the atmosphere of a cathedral. For many years it was closed to the public, but after a difficult reconstruction it became a popular tourist destination. The site offers not only a glimpse into the history of technology, but also a unique aesthetic experience. The water tower is open for tours and often hosts cultural events.