As little as a century ago, the Paljassaare peninsula was in fact two small islands. A former military zone turned conservation area includes both abandoned military structures as well as diverse nature. It has been designated a NATURA 2000 site due to the pan-European importance of this birdsite. Thanks to its mosaic landscape this area draws a variety of bird species making it the best place for birdwatching in Tallinn.

Only a century ago, the small Karli Islands were where Paljassaare is now. The Karli islands (later, the entire peninsula) were used for military purposes until the end of the Soviet occupation.