Using the open pipe by the pond we reached the abandoned sewage treatment plant. The sewer runs about 500m underground and about every 10m there are open outlets through the sewer. The tunnel further splits into two narrow tunnels (you can't climb out there, you need some exploration and waterproof cameras)

Exploring an abandoned and unfinished shopping centre in Prague's Palmovka district. The building can already be seen when exiting the metro at Palmovka station. But there are a lot of junkies there, so watch out :-)