Years before the monster earthquake shook Japan and unleashed a massive tsunami in March, Google had mapped the roads of northeast Japan with its Street View project, as it had done in many parts of the world.
Shortly after the disaster, Google sent video teams back to the worst-hit areas to cover 44,000 square miles' worth of devastation.
With that material now in hand, Google has just released Memories for the Future, an interactive website that allows users to scroll through Street View images of Japan before and after the disaster.
Drag the slider right and left.
"We wanted to photograph and record traces of the disasters to preserve them for the next generation, so even if the areas are perfectly rebuilt, no one would ever forget what happened there," said Ken Tokesei, Google's Project Management Director in the Asia-Pacific region.
By selecting a point on a map of Japan, users can see what a specific area looked like several years ago. And with a single click, they can compare that site with the images taken by Google after the quake and tsunami - though in some cases, there is very little left to compare.
Some of the earlier images show signs of life - cars, bikes, people - but after the earthquake and tsunami, the streets are hauntingly empty.
The cruel irony of natural disasters is seen in full view as some parks, roads and buildings remain virtually unscathed even in the hardest-hit parts of the country. Other areas depict not mere damage, but utter destruction with once-dense, residential streets reduced to rubble.
In Sendai, a bike shop is razed to the ground. Tall grass grows where the building once stood, as though it never existed at all. By showing these scenes side by side, Google Street View's 360-degree imagery tells a story isolated photographs cannot fully convey.
Tokesei hopes that Memories for the Future will increase the momentum of the recovery by aiding researchers and city planners. "But more importantly," he says, "we hope the imagery will make the world realize the scope of the disaster and see through a virtual tour that these communities are still not fully recovered and need the world's support."