The Brasilia Cathedral in Brasilia, Brazil is a modern church designed by Oscar Niemeyer. It took 11 years to build. The actual worship area is below ground level, which could lead to its demise. This house of God was built to last a thousand years, but will it without humans?
2 days after people: The power fails in Brasilia and the cathedral slowly goes black. The three angels hanging from the ceiling will never see another worshiper.
1 month after people: The Paranoa River is starting to top the banks. Being a half mile away from the river, it should be okay, for now.
1 year after people: The nave of the church is flooding. The waters of the river have reached the tunnel and have started to flood the church. The plaster on the walls is starting to flake off, too.
25 years after people: The stained glass above the nave has broken letting in even more water. The cables holding the three angels up are becoming stressed beyond failure point. Finally, the first angel falls, hitting the others causing the others to come down with it and they splash in to the water below.
75 years after people: The reinforced concrete supports on the outside are eroding away. The rebar on the inside is rusting and causing the concrete to become weak. Suddenly, one of the supports breaks sending the roof of the cathedral crashing into the river.