Linnahall

When Moscow hosted the 1980 Summer Olympics, the sailing events were held in Soviet-occupied Estonia. Linnahall, originally called the "V. I. Lenin Palace of Culture and Sport," is a sprawling ziggurat-like complex designed to host the Olympic regatta. Today, it's all but abandoned, and mostly visited by graffiti artists and curious tourists.

The structure was commissioned by the Soviet Union in part to show the world their mastery over concrete-pouring. In addition to its massive 5,000 seat amphitheater, it includes an ice hall, a small seaport, and a heliport. The ice hall closed in 2009, and the concert hall in 2010.

The hurried construction of the building has begun to show over the past 30 years as the poorly finished rock crumbles. The arena is still used from time to time when a large enough event comes to the country, but generally, the huge structure sits empty. Locals and tourists still enjoy taking the external steps up to the roof of the hall, which provides a rather stunning view of Tallinn's skyline.

As many important buildings in the Soviet Union, the design of Linnahall was planned to be also useful during wartime. The location by the sea and the flat roofs made it a perfect spot for tanks or cannons to cover the whole bay of Tallinn, in case the "evil" Finns would want to conquer the city.

In 2019 the City of Tallinn announced plans to transform the structure into a conference center, including an opera and concert hall.