We arrived in Joutsa, a two-hour drive from Helsinki, to a beautiful lakeside cabin. These cabins are quite common in Finland since the country has well over 100,000 lakes. Upon arrival, I was introduced to a spear (and the proper technique to use it in case of a bear attack). It somehow managed to make me feel less safe. Then, it was straight to work: some went mushroom picking while the others started to prepare the crayfish, which were waiting in a sumppu, or chest, submerged in the lake next to the pier. These were good-sized members of signal crayfish, a species that has largely invaded Finland's lakes.