On April 28, 1947, Norwegian ethnographer and adventurer Thor Heyerdahl and five crew mates set out from Peru on the self-built raft Kon-Tiki to prove that Peruvian natives could have settled Polynesia. With Kon-Tiki, Heyerdahl sailed 8,000 km across the Pacific Ocean in a self-built raft from South America to the Tuamotu Islands to demonstrate that ancient people could have made long sea voyages, creating contacts between apparently separate culture
On April 6, 1829, Norwegian mathematician Niels Henrik Abel passed away. Abel is well known in mathematics for proving the impossibility of solving the quintic equation by radicals. In parallel to Évariste Galois - who also died very young - , he laid the foundations of group theory.