The Botanical Gardens seen from the Tower.
Bontanicheksi Sad is the home of the dark ones.
Overview
The Botanical Garden is where the dark ones live and breed. Not much is known of the garden, as the only appearance is near the end, and depending on the player's actions, is wiped out by the missiles along with the dark ones.
Looking from the tower, it appears the Garden has mutated hugely, either from the dark ones or naturally. The landscape appears to be scorched black, with some orange glowing growths on huge, black vine like plants growing across the area of the Botanical Garden, and the surrounding city blocks. From observation with a scoped weapon on top of the Tower, it can be seen that there is two notable area's seen in the Botanical Gard, one being a spire like structure, and a cluster of vines to its right.
Artyom's Interaction
When Artyom was a boy, he was challenged by three of his friends to go with them to the neighbor Botanical Garden which was already abandoned. When they were young Artyom and his friends arrived to the abandoned station equipped with a flashlight and an old double barrel one boy stole from his father, they found a stairway leading up and followed it. Artyom and his friends reached the top of the stairway and found a hatch, they opened the hatch and saw something amazing -- the sky. Luckily for them it was dark so their eyes weren't hurt. They stared at the sky for some minutes and then heard a horrible scream coming from nearby ruins, Artyom and his friends panicked and rushed back through the Botanical Garden to VDNKh, leaving the hatch open.