The collapse of every building was not accidental.

The collapse of every building is not accidental: when a building collapses, no brick is innocent.

Apartment building is a multi-storey and multi-unit building, which is a common architectural mode in cities with few land and many people.

Among them, the steps of the building shall not be owned or used by the same group of people.

The infrastructure of the building includes tap water, power supply, sewage pipes, doors, windows, load-bearing walls, public corridors, stairs, elevators, lightning rods, roofs, water tanks, telephone lines, etc. If you call it a mansion, there may be private clubs, swimming pools, tennis courts, gyms, property management and so on.

There are even shopping malls, cinemas and so on in some buildings.