![There’s a first layer made of steel\Nand a second one of reinforced concrete.
There’s a first layer made of steel\Nand a second one of reinforced concrete.](https://content2.mcqstudy.com/ss/mm-1-8-00:12:14.405.jpeg)
There’s a first layer made of steel
and a second one of reinforced CONCRETE.
Money Heist Season 1, Episode 8
![80 centimetres of reinforced concrete.
80 centimetres of reinforced concrete.](https://content2.mcqstudy.com/ss/mm-1-8-00:12:32.205.jpeg)
80 centimetres of reinforced CONCRETE.
Money Heist Season 1, Episode 8
![The structure is covered\Nwith concrete walls
The structure is covered\Nwith concrete walls](https://content2.mcqstudy.com/ss/mm-3-3-00:03:34.083.jpeg)
The structure is covered
with CONCRETE walls
Money Heist Season 3, Episode 3