I went to a high school in the UK that had been built on an ex landfill site. I was only there for just over a year, but the methane alarm went off a few times then, resulting in evacuations.

The school was relatively new, having allegedly been built around 2003 because Asda (then owned by Walmart) wanted to move a supermarket from one side of the road to the other.

According to folklore the developers paid for the design from US architects who specialise in prison architecture – which was believable because it looked and felt much like a small prison.