In 1961, Yuri Gagarin became the first person to venture beyond Earth's atmosphere. Since his journey, about 450 people – astronauts, civilians, and "space tourists" – have explored space. Follow this slideshow to learn about notable firsts for space exploration.

















Yuri Gagarin
Photo source: NASA
Alan Shepard
Photo source: NASA
John Glenn
Photo source: NASA
Valentina Tereshkova
Photo source: NASA
Alexei Leonov
Photo source: NASA
Ed White
Photo source: NASA
Neil Armstrong
Photo source: NASA
Sally Ride
Photo source: NASA
Guion Bluford
Photo source: NASA
Mae Jemison
Photo source: NASA
Eileen Collins
Photo source: NASA
Andy Thomas
Photo source: NASA
John Glenn
Photo source: NASA
Dennis Tito
Photo source: fas.org
Yang Liwei
Photo source: spacedaily.com
Peggy Whitson
Photo source: NASA
Zhai Zhigang
Photo source: spacefacts.de