This is one of the most amazing places here in 798. Go inside, stand in the middle and jump very hard or clap very loud. You can also scream very loudly. You will see what we mean. (And then imagine starting a firework in there. We did on New Years. Don't repeat - it might get you in trouble! ;-) )
This tank actually had the possibility to grow by the amount of gas being stored inside. Have a look at the walls, you will see 5 or 6 layers of walls, which will automatically would rise once more gas is pumped in - there are rails for the walls to go uphill. We assume this used to be a gas storage for the plants around, such as the power plant and heating plants.