Toompark is established on the grounds of the former earth fortifications around the Snelli Pond. The pond is the only remaining part of the moat (this particular section being completed in 1760‑ies) once surrounding the city. The pond owes its name to the city gardener Snelli whose house and garden were located on its shore in the 19th century. The opening of Patkuli staircase connecting Toompea (Upper Town) and Lower Town dates back to 1903. Toompark boasts the vast variety of trees. This multitude of species has been caused by the relief itself as well as by the creation of the park in several stages at different times. Toompark is the richest of all parks in the centre of the city from the point of view of plant species and sorts. There were ca 110 species of ligneous plants growing in the park in autumn 2007.