The city is situated on the banks of the Dâmbovița River, which flows into the Argeș River, a tributary of the Danube. Several lakesthe most important of which are Lake Herăstrău, Lake Floreasca, Lake Tei, and Lake Colentinastretch across the northern parts of the city, along the Colentina River, a tributary of the Dâmbovița. In addition, in the centre of the capital is a small artificial lakeLake Cișmigiusurrounded by the Cișmigiu Gardens. These gardens have a rich history, having been frequented by poets and writers. Opened in 1847 and based on the plans of German architect Carl F.W. Meyer, the gardens are the main recreational facility in the city centre.