Overlooking the sea in Helsinki, Observatory Hill covers 6.7 hectares and was once part of a chain of watch hills whose fires guided sailors. The Ulrikasborg fortification was built here between 1748 and 1750, and in the 1830s the university observatory designed by C. L. Engel rose on the hill; it reopened in 2012 as a museum of astronomy. Its final layout follows a plan by city gardener Svante Olsson.
The slopes hold nearly 100 species of trees and shrubs, including the only ginkgo in central Helsinki. Sculptures include Robert Stigell's Shipwrecked from 1898 and a memorial to the Jewish refugees deported from Helsinki in 1942. There is a playground, and dogs are allowed.
