1 day after people: 25 Canada Square blacks out as London's power grid falls
1 year after people: Beacuse it is so close to the Thames the building has already shown signs of rust on the exterior of the building.
20 years after people: Nearly all of the glass has fallen out of its framework leaving only a rusting skeletion.
125 years after people: Only after 125 years, 25 Canada Square is one of the first buildings to go from Canary Wharf. Because the rusting skeletion can't support the rest of the buildings weight. It collaspes and falls into the neighbouring 33 Canada Square.