Catherinethal ("Catherine's valley") is a Petrine Baroque palace of Catherine I of Russia in Tallinn. It was built after the Great Northern War to Nicola Michetti's designs by Gaetano Chiaveri and Mikhail Zemtsov. In the 20th century the Estonian version of the name, Kadriorg, gained currency and came to be applied to the surrounding district.
After the successful siege of Reval in 1710 Peter the Great of Russia bought a Dutch-style manor house at Lasnamäe for his wife Catherine. The house today is the result of a drastic renovation ordered by Nicholas I of Russia in 1827.
The new palace was started on 25 July 1718. Peter and Catherine visited the unfinished residence on several occasions, but after the emperor's death in 1725 Catherine showed no interest in the seaside property. The great hall with Catherine's initials and profuse stucco decor (attributed to Heinrich von Bergen) survives, but many other interiors have been altered. The gardener Ilya Surmin was responsible for the flower garden with two fountains and the so-called mirage garden on several levels. The layout of the park shares similarities with that of Strelna.
The palace currently houses an art gallery. The KUMU Museum is sited in the park.
Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.