Tähtitorninvuori

thumb|Tähtitornin vuori thumb|The Shipwrecked sculpture Tähtitorninvuori or Tähtitorninmäki (Swedish: Observatorieberget/Observatoriebacken; ) is a rocky hill about 30 meters high in Ullanlinna, Helsinki, next to the South Harbor. The hill is mostly a park, but there are also a few public buildings.

At the top of the hill, at the southern end of Unioninkatu, is the Helsinki University Observatory, which was completed in 1834 and is named after the observatory towers. Today, the Observatory serves as a public center for astronomy and is not used for research purposes. Astronomical observations there can no longer be made because the city lights completely obscure the dim objects in the starry sky. Researchers can make observations e.g. In Metsähovi in Kirkkonummi or abroad.