The Tournakis or Theocharis residence, located at the corner of Dimokratias and Sikyonos streets in Kiato, was built in 1890 and is the only one of the four buildings designed and constructed by the renowned architect Ernst Ziller in Sikyon that remains in excellent condition. Known as the "mansion" by the old residents of Kiato, it was originally built for the family of Efstathios Tournakis, a doctor and politician who had close ties with Ernst Ziller, which explains the architectural oversight by the famous German architect. In 1919, it was sold to Grigorios Theocharis, and in 1981, it suffered severe damage during the Alkyonides earthquake. In 1997, the Municipality of Kiato purchased the building with the intention of preserving and restoring it.

It is a single-story, neoclassical-style residence with a basement and distinct decorative elements. One of its most remarkable features is the unique ceiling murals that adorn its rooms. The building is currently undergoing restoration, with plans to convert it into a Municipal Art Gallery upon completion, primarily showcasing the donated collection of paintings by the renowned Sikyonoian painter with an international career, Kostas Paniaras.