Earth is now slightly better prepared for an agricultural apocalypse: The "Doomsday Vault" is 20,000-species stronger as of this week—its sixth birthday. A new wave of seed varieties were deposited that hail from more than 100 countries and represent a "sort of winter Olympics of crop diversity," per the director of the trust that maintains the facility. Among them: varieties of Japanese barley that will ensure the world won't lose its access to miso should disaster strike, reports the Independent. Samples of that key miso ingredient, along with Brazil's "common bean," a rare Tennessean red okra, and nearly 200 types of wild potato have been added to the 820,619 samples that have been placed in the vault since it opened in 2008. It was constructed to hold up to 4.5 million seed samples, and sees one to two new deliveries each year, notes the Guardian. The Doomsday Vault, more formally known as the Svalbard Global Seed Vault, functions as a sort of backup, holding duplicates of seed samples otherwise housed in gene banks around the world. But this location is about as secure as possible: It sits within a mountain on a remote island in the Svalbard archipelago, between Norway and the North Pole, behind four sets of air-locked doors. It can weather nuclear war, an asteroid strike, and climate change. That hardiness likely influenced Japan's decision to send seeds for the first time. The BBC reports that the 2011 earthquake and tsunami convinced the Barley Germplasm Center at Okayama University to pony up 575 samples after realizing its own storehouse wasn't impenetrable.