The Crystal Cathedral is a megachurch constructed solely of glass and steel.

The megachurch is a greenhouse

1 year after people; Without people, only rainstorms clean the Crystal Cathedral's 10,000 panes of glass. Open panels let dirt and seeds blow into the church's interior.

20 years after people; Plant life now grows in the Crystal Cathedral's interior and the megachurch has become a greenhouse.

50 years after people; The main part of the church still stands but the the Prayer Tower has been sinking for years. Finally the lean becomes to much the tower to bear and it collaspes but luckily it doesn't hit the cathedral.

75 years after people; The structure's corroded steel finally gives out and the Crystal Cathedral collapses.

The steel frame collapses