Károly Kaán observation tower, Fire lookout tower on Nagy-Hárs-hegy hill, Hungary

The Károly Kaán observation tower stands on the 454-metre summit of Nagy-Hárs-hegy in Budapest's II district. Its base and lower one-and-a-half storeys have a reinforced concrete frame clad in stone, while the upper sections and stairs are timber. From the top level a full 360-degree panorama opens over Budapest and much of the Buda Hills.

A wooden lookout stood on the summit of Nagy-Hárs-hegy before the 1980s but collapsed through lack of maintenance. The present tower was built in 1988–1989 for the Pilisi Állami Parkerdőgazdaság, the predecessor of Pilisi Parkerdő Zrt. Its base and lower one and a half levels are a reinforced-concrete frame clad in stone, while the parts above and the stairs are timber. A full renovation and structural reinforcement followed in summer 2016.

The tower is named after Károly Kaán, a forest engineer whose work shaped forestry practices in Hungary. His name connects this location to the country's modern woodland management history.

The observation tower is accessible via wide paths and sits on a hill, so reaching it requires some climbing effort. The best time to visit is during clear weather when visibility extends over longer distances.

From the different levels of the tower, visitors can spot the Hungarian Parliament, Castle Hill, and multiple mountain ranges. This layered view offers perspectives that would normally require visiting several different vantage points around the city.