Sisu is a Finnish term that lacks a direct translation in English. It’s a package of grit, determination, and resilience, which defines the Finns’ national character.
In other words, Finns are tough f#ckers. Tough enough to fight off the Russians and the Nazis. For fun, they cross-county ski, literally across the country, in minus 40 degrees Celsius. If you don’t know what minus 40 degrees Celsius feels like, it’s snot-freezing cold. So cold, your eyelashes grow icicles. All your caloric energy goes towards warming your bladder so your piss doesn’t solidify.