Scientists are at work deep in the mountains of central Japan. They hope to prove a theory of Albert Einstein's. Two hundred meters underground, inside an abandoned zinc mine, the researchers have laid two pipes in tunnels at right angles, each three kilometers long. The tunnels are so long it's impossible to see light at the ends. The tunnels are also so long that on this job, the scientists move around by bicycle.

Young Japanese urbanites' growing interest in country living is pushing them out of the city to follow family ties in their grandparents' hometowns. It is a reversal of a trend that began in the 1960s, when big cities were booming as people flocked to metropolises for a taste of the urban lifestyle.