On the site of the mansion of the Gersei Pethő family, the construction of the castle was started by Kristof Festetics in 1745. It gained its final - neo-baroque - form in the 1880s. It miraculously avoided destruction during the second World War. As Helikon Castle Museum, it has been independent since 1974. Its library of 100000 volumes is the only complete aristocratic collection in Hungary to have been left intact. It is a museum (permanent and temporary exhibitions), a conference and cultural centre.
On the western façade of the stately home facing the park, there is a distinctive difference between the original Baroque parts and the towered part built in the 1880’s. The library wing was built by György Festetics between 1799 and 1801. There are several statues in the park; that of St Helen used to stand on the county boundary on the Iszap (Mud) Island, it was taken to Fenékpusztára and from there it was taken here.