Laser cooling and trapping techniques makes it possible to confine small clouds of atoms and cool them down to a few billionth degree above absolute zero. Under such extreme conditions the atoms can drastically change their behavior and condense into a single common quantum state, which makes it possible to directly image a quantum mechanical wavefunction in experiments. Such ultracold quantum gases provide a fascinating demonstration of the quantum nature of matter, and their laboratory production in cold-atom experiments has since ushered in a wide-spread revolution in many areas of physics, that continues to reveal new insights into fundamental aspects and applications of quantum mechanics.