A tour inside the "Doomsday" Global Seed Vault in Svalbard, Norway, which I mentioned here about a year ago.
The seedbank is constructed 120 metres (390 ft) inside a sandstone mountain at Svalbard on Spitsbergen Island. The bank employs a number of robust security systems. Seeds are packaged in special four-ply packets and heat sealed to exclude moisture. The facility is managed by the Nordic Genetic Resource Center, though there are no permanent staff on-site.Wikipedia.
Spitsbergen was considered ideal due to its lack of tectonic activity and its permafrost, which will aid preservation. The location 130 metres (430 ft) above sea level will ensure that the site remains dry even if the icecaps melt. Locally mined coal provides power for refrigeration units that further cool the seeds to the internationally-recommended standard −18 °C (−0 °F). Even if the equipment fails, at least several weeks will elapse before the temperature rises to the −3 °C (30 °F) of the surrounding sandstone bedrock.
Prior to construction, a feasibility study determined that the vault could preserve seeds from most major food crops for hundreds of years. Some seeds, including those of important grains, could survive far longer, possibly thousands of years.
It's terrifying to imagine a day when we will need to resort to vaults such as the one Svalbard, but it's somewhat reassuring to know that people are taking the steps to insure that we have somewhere to turn if climate change brings on global crop failures and crop extinction.