Trojská 13a, Social security office in Libeň, Czech Republic

Trojská 13a is an administrative building from 1974 on a hill above the right bank of the Vltava, on the border of Libeň and Kobylisy. Its architect was Jovan Jovanović from the former Yugoslavia; concrete pillars in front of the facade form sunshades. A lower building was added to the southwest in 1979.

The building was designed by Jovan Jovanović, an architect from the former Yugoslavia, and completed in 1974 on the slope above the right bank of the Vltava between Libeň and Kobylisy. A lower annex was added in 1979. Chemopetrol occupied it first, then Benzina and, from 1995, the Unipetrol headquarters; in 2002 it was sold for 214 million Czech korunas to the Czech Social Security Administration for Prague 8.

The nickname Drákulov comes from the building's resemblance to a ruined castle, given by locals. The concrete pillars in front of the facade act as sunshades. Since 2002 the Czech Social Security Administration for Prague 8 and the district financial office have used the building.

The building is not open to the public; it can be viewed and photographed from the outside. It stands on a hill above the right bank of the Vltava, on the border of Libeň and Kobylisy in Prague 8, at Trojská 13a. The concrete pillars in front of the facade are best seen from the street.

The concrete pillars in front of the facade act as sunshades, and the building's castle-ruin look earned it the nickname "Drákulov". After a facade renovation in 2017 its colour changed from light beige to grey.