The first place, the Algerian stone pillar. Maybe many friends don't know Algeria. Algeria is in North Africa, adjacent to the Sahara Desert. The most famous place in this area is the local stone pillar.

The second is Greater Zimbabwe, also known as the "ghost town". This place used to have a large population, but suddenly it became a ruin, and the people living here disappeared.

The third place is Yinghao, an important city in indus valley civilization, but in 2600 BC, everyone in the city died at the same time.