Towering majestically over the city is the mighty three-winged baroque complex the Heidecksburg. The castle was built in the second half of the 18th century on the ruins of a Renaissance castle that burnt down in 1735 and was the residence of the Princes of Schwarzburg-Rudolstadt until 1918. The interior of Heidecksburg Castle contains Architecturally and culturally valuable treasures. The highlight is the Ballroomwhich is one of the most beautiful of the German Rococo period.

Visitors can tour various areas of the Heidecksburg State Museum:

Banqueting and living rooms - Porcelain Gallery - "Deep Well" - Picture Gallery

"Rococo en miniature"

The museum's visitor magnet is the impressive miniature world "The castles of the praised island", which is unparalleled in the German-speaking world. With unbelievable precision, Manfred Kiedorf and Gerhard Bätz created miniature buildings complete with detailed interiors on a scale of 1 : 50 over the past 50 years. Ten castles, around 1,000 individual figures and 1,000 furnishings were created in meticulous detail.

The imaginary origin of the two kingdoms Dyonia and Pelaria lies more than 50 years ago in a role-playing game, which the artists had imagined as teenagers and developed to perfection up to the present. Thus, the fictional planet Centus is embellished with rulers' residences, pleasure palaces, pavilions, a mausoleum and other stylish buildings that provide a home for hundreds of imaginary characters. Each object has its function and history, even the smallest drawer in the elaborately decorated cabinets can be opened and their inner workings marveled at (with a magnifying glass). Each imagined person is a personality with a name, title, family tree and a comprehensive character, imagined to the last whim.