It’s a natural process that things become covered over time and nature reclaims them. Myko commented: “Soil and leaves can cover them, floods can bring silt and water, or dust settles on them.”

Of course, it’s not only nature that’s responsible for that. “People have a habit of often building in the same locations and on top of their previous efforts—they might build over the foundations of old buildings or atop their ruins.” That means that things like this mosaic slowly become buried over time.“

There are parts of old Mesopotamia, for example, that have hills in areas that should be entirely flat,” Myko said. These are actually the remains of entire towns, where residents built layer after layer until the whole thing became meters tall.