Building a 10,000-year machine required diving into both history and the present to see how artefacts have lasted.

When I visited Japan recently, I witnessed the 66th cycle of a ritual that began more than 13 centuries ago. I watched as Crown Princess Masako led a procession of Shinto priests carrying treasures from the old temple to the new. In Ise, they have been rebuilding the grand Jingu shrine with wood and thatch every 20 years since at least the 7th Century. As part of Shinto ritual, this not only keeps the structures intact even when made out of relatively ephemeral materials, but it allows the master temple builder to train the next generation.