Mařenka viewtower, Observation tower in Štěměchy, Czech Republic.

Mařenka viewtower is a 31-metre observation tower on Mařenka hill (711 m), the highest point of the Třebíč district. Its design is a spherical triangle: a nine-metre stone-clad concrete base carries a wooden structure, with 156 steps of a spiral metal staircase leading to the viewing platform at 28 metres. The project was designed by Ing. arch. Martin Franěk of Ateliér Penta, v.o.s. in Jihlava.

A wooden triangulation tower built in 1941 stood here and was used by German troops as an observation post during World War II; a gale brought it down in 1957. The Podhůří Mařenky association of municipalities revived the plan in 2003, obtained a building permit in 2009 and a three-million-crown ROP NUTS II grant in 2010, and the current tower by architect Martin Franěk was opened on 27 October 2012.

The tower's name comes from the hill Mařenka, whose 711 m summit is the highest point of the Třebíč district. In 2022 Miroslav Šafránek built a one-metre model of the tower, which travels around the surrounding villages as part of the celebrations marking ten years since the tower opened.

The viewing platform sits 28 metres up, reached by 156 steps of a spiral metal staircase above a nine-metre stone-clad concrete base. The tower stands on Mařenka hill at 711 m, the highest point of the Třebíč district. On exceptionally clear days the Alps, 150 to 180 km away, come into view.

The original wooden tower, built in 1941, was reportedly so tall that Austria could be seen from it; German troops used it as an observation post during World War II. In 2016 a Canadian who had been captured there during the war returned to visit the site.