Vieta, Vilniaus apskritis
Kalnų gamtinis rezervatas is a strict nature reserve of about 64.7 hectares within Pavilniai Regional Park, in the Naujoji Vilnia part of Vilnius. Established on 10 December 1998, it protects the park's most natural ecosystem: a zone of spring-fed erosional fans and ravines on the Rasos-Ribiškės upland, covered by spruce and oak communities. The forest is rich in small mammal and butterfly species. Economic and recreational activities are prohibited; access is limited to scientific research and educational purposes.