Château d'O is one of the old country mansions or follies surrounding the French city of Montpellier. It was built by wealthy merchants from the 18th century onwards. The South entrance leads to the 18th century mansion, while North entrance leads to modern buildings, with Théâtre Jean-Claude Carrière. It is now a main sight of the city of Montpellier.
References:Bomarsund fortress and garrison was built in 1832-1854 by Russian Empire to defence Åland Islands against enemies. British and French fleet attacked against it during the Crimean War in 1854. After a week of fighting the British stormed the remaining fort. Anglo-French forces destroyed it totally after battle. In the Treaty of Paris 1856, the entire Åland Islands were demilitarized, which is a status that has been preserved until this day.
Nowadays there are some ruins left and fortress area is open for visitors.