The remains of the Castle can be visited
Haineck Castle

The Haineck castle ruin, a hilltop castle, is on a mountain spur above the municipality of Nazza in the Wartburg district. Its location on the western edge of the Hainich and its well-preserved remains.
History+
The construction of Haineck Castle is believed to have occurred around 1392, initiated by Landgrave Balthasar. It served to secure the borders of the Landgraviate of Thuringia against incursions from the Mainz Eichsfeld and the free imperial city of Mühlhausen. Around 1400, the Lords of Wangenheim served as bailiffs, followed by Hans and Wetzel von Creuzburg in 1416. In the 15th century, the dominion changed hands several times, often through pledging. In 1448, it passed to the Counts of Henneberg.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Roland Neubert, Halle (Saale)
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 51.1194, 10.3425