Vitosha Mountain TV Tower

Vitosha Mountain TV Tower, better known as Kopitoto after the rock outcrop it stands on, is a 186-metre tall TV tower built of reinforced concrete on Vitosha Mountain near Sofia, Bulgaria. The footprint of the tower has the shape of a hexagon with three of the sides extended. From the tower there is a commanding view of Sofia, and the tower can be seen from everywhere in Sofia, making it a landmark of Sofia's skyline. It is the second tallest television tower in Bulgaria.

Source: Wikipedia