The slope of Mustamäe is a reminder of the Ice Age and the former seaside zone.
The height of the slope within the protected area is 15-30 meters and the length is about 3 km.
In the forest of Rõõmuallikas, 24 springs open in a stretch of about one kilometer during periods of high water, the largest of them is Rõõmuallikas (the Spring of Joy).
Very different types of forests grow in the protected area - heath and pines, spruce and spruce-mixed forests and decidous forests. A swamp forest is remarkable in urban context .
Ten protected plant species grow in the protected area, the most remarkable of them is the sand pink growing on sand dunes.
More than 120 bird species have been registered in the protected area. Traditionally shy of humans, the northern goshawk has been nesting in the protected area for more than ten years.
Õpiringi boulders named after the geography study group of the Tallinn Society of Young Naturalists that surveyed them already in 1935
In the 19th century, the area was also known as the Blue Hills (Sinised mäed), because the forest looked like a blue stream from a distance.
The manager of the protected area is the Estonian Environmental Board.
