Blansek, Castle ruin in Suchdol, Czech Republic.

Blansek is a castle ruin near Suchdol featuring a two-part core structure and a tall front section dating from the 13th century. The stone structures display typical medieval defensive architecture with multiple building complexes.

Blansek was founded by Olomouc bishop Bruno of Schauenburk in the second half of the 13th century and first mentioned in 1275. It became the centre of a feudal district with over 30 manors; from 1396 it was granted as a fief, first to Erhart of Kunštát and Skal. In 1461 it is recorded as deserted after a fire.

The core of the ruin stands directly above the Punkva valley, on the road leading to the Punkevní Caves, whose entrance lies below the hill opposite the castle. Part of the crumbling masonry was pulled down in the 1930s so it would not fall onto that road, and the wall tops remain loose, so keep to the paths and away from the foot of the walls.

In the 1930s part of the crumbling masonry was pulled down so it would not fall onto the road to the Punkevní Caves, which were then being opened to the public. The walls remain unstable, with loosened crowns threatening to collapse into the Punkva valley.