SPUTNIK / SCIENCE PHOTO LIBRARY SPUTNIK / SCIENCE PHOTO LIBRARY
Hot air balloon. The pilot operating the propane burners or a hot air balloon. The burner are used to heat the air trapped in the envelope. Hot air is less dense than cooler air, so the balloon becomes buoyant. Photographed at Sergiyev Possad, Russia, in 2010.
Model release not available. Property release not available.