While exploring the historic Ano Poli, the Old City or Upper Town, you will stumble upon the old city wall and the Heptapyrgion. It is a Byzantine and Ottoman-era fortress. You can pay to see the renovated interior part, which used to serve as a prison from 1890 to 1990. Enjoy your urban hike up to the monument, check out the panoramic views and sip a frappe in one of the charming cafes in the area. Also known as Edy Kulѐ or Eptapirgio, 'Seven Towers', is a medieval fortress with towers in the northeastern part of Thessaloniki. Despite its name, the fortress has ten towers. The fortress was built in the IX century, and some parts of it were built later. Like the White Tower, it was used as a prison from the late 19th century until 1978.

Also known as the Rock Church, this place is carved straight into granite in the middle of Helsinki. From the outside, it kind of looks like a grounded spaceship. Inside, the rough stone walls, copper dome, and skylight ring give the space a quiet, otherworldly feel. It’s still used for services, but you’re just as likely to catch a concert here, thanks to the natural acoustics, which are genuinely impressive.

Founded in 2001, this museum is devoted to showing the rise and fall of the labor camp system in Russia called Gulag. Here you can find both permanent and temporary exhibitions as well as concerts and events.