The Toome Hill, rising above Old Town, has always been strategic military position. Tartu's original settlement, Tarbatu, was established here in 600AD, and if you trace the hill's outline on a map, you can still see the shape of fortifications built here in the 17th and 18th centuries.
The western part of the hill is clearly dominated by the ruins of the 13th-century cathedral (Toomkirik) that has been decaying since the Livonian War (1558-1583). The sanctuary, which is still in a quite good condition today, accommodates the University’s history museum. Here you can get a broad overview of academic research and teaching in Tartu.
The old observatory of Tartu was constructed in 1811. It was the most modern one in Europe in the 19th century.References:
Narikala is an ancient fortress overlooking Tbilisi, the capital of Georgia, and the Kura River. The fortress consists of two walled sections on a steep hill between the sulphur baths and the botanical gardens of Tbilisi. On the lower court there is the recently restored St Nicholas church. Newly built in 1996–1997, it replaces the original 13th-century church that was destroyed in a fire. The new church is of 'prescribed cross' type, having doors on three sides. The internal part of the church is decorated with the frescos showing scenes both from the Bible and history of Georgia.
The fortress was established in the 4th century and it was a Persian citadel. It was considerably expanded by the Umayyads in the 7th century and later, by king David the Builder (1089–1125). Most of extant fortifications date from the 16th and 17th centuries. In 1827, parts of the fortress were damaged by an earthquake and demolished.