Ruins of the Convent of St. Birgitta (Püha Birgittale)

From www.tourism.tallinn.ee:

The Convent of St. Bridget was the largest convent of Old Livonia.

Established by Tallinn’s wealthy merchants in 1407, construction was begun on the convent itself immediately. It is a typical example of late Gothic churches in Tallinn. The church was destroyed in the second half of the 16th century, and today only the western limestone gable, 35 meters high, and side walls remain standing. In the 17th century, a farmers' cemetery developed in front of the ruins.

The convent was unique in that its constitution allowed male priests to live there and organise everyday religious ceremonies and processions on religious holidays. There are also tales of secret underground passageways between the convent and the city of Tallinn.

Today, the convent is a pleasant spot for relaxation and sightseeing. In addition to the impressive ruins themselves and their surrounding greenery, the site is a venue for open-air concerts and a convent day celebration, where a traditional fair takes place in the convent grounds.