I recently had the chance to go flying in a glider. A glider is an airplane without an engine, so it gets towed up by a powered plane. The glider is released at the desired hight, and the glider pilot slowly descends back to the airport. However, gliders actually are capable of climbing higher as well, using thermals and updrafts. Thermals are pockets of rising hot air, which can carry a glider up.
Gliders are the sailboats of the sky, which is why they are sometimes referred to as sailplanes. With no noise but the wind over the cockpit, it really is a beautiful experience.
The video above is some footage I took on my first glider flight.