The United Nations Postal Administration released commemorative stamps in 2011 to mark the 50th anniversary of Gagarin's flight.

Not so long ago, humanity took its first step beyond Earth. For thousands of years, we gazed at the stars, dreaming of what lay beyond. Then, on April 12, 1961, one man left the planet and changed history forever. That morning, Soviet pilot Yuri Gagarin climbed into a small, spherical spacecraft named Vostok 1. The countdown began. The engines ignited. As the rocket roared toward the sky, he called out, 'Poyekhali!'—'Let's go!' And just like that, Earth had its first space traveler.

For 108 minutes, Gagarin orbited the planet, watching the world from a view no human had ever seen before. When he landed safely back on Earth, everything had changed. Humanity had entered the Space Age. His flight sparked the race to the Moon, the dream of living on Mars, and much more. Decades later, in honor of his achievement, the United Nations declared April 12 as the International Day of Human Space Flight. Pictured here is the view from the cupola of the International Space Station, showing the vast South Pacific Ocean. It is a reminder of how small Earth is in the grand cosmos—and how far human spaceflight has taken us.