Botanical Garden of the Comenius University (Slovak: Botanická záhrada UK) is the only botanical garden in Bratislava the capital of Slovakia. It is located between the Old Town and Karlova Ves districts by the river Danube and it contains over 4,000 plant species (including 1,200 species of cacti) covering an area of 7 hectares. Botanical Garden of the Comenius University is the oldest public botanical garden in Slovakia. It is open to the public only from 1 April to 31 October each year during the day and the entrance is paid.