Tuskulėnai Manor is Žirmūnai's oldest extant architectural structure. The manor was built in 1825, following a design by Karol Podczaszyński in the neoclassical style. It consists of the principal building (the palace), an "officina" (storage house), and several adjacent buildings, including a small eclectic chapel of St. Theresa located about 100 metres south of the principal building. The "Little White Manor", also known as the villa of Franciszek Walicki, was built in 1866 further south from the manor, acquired by Walicki in 1928, and reconstructed to serve as a summer residence. All of these structures have been restored by 2009, and are a part of the 7.5-hectare Peace Park ("Rimties parkas") that includes the Tuskulėnai Manor, hosting a museum of martyrology in Lithuania in the second half of the 20th century (a branch of the Lithuanian Museum of Genocide Victims), restored landscaping, as well as the columbarium.