For 20 years, astronauts have been shooting photos of Earth from the space station. Like everything the astronauts do, they are trained for this job. And like everything they do, there is purpose and intention behind it.

Producers & writers: Kathryn Hansen and Michael Carlowicz

Footage contributed by: Pola Lem

Images: Astronaut photographs are provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. Action video from ISS provided by NASA Johnson Space Center.

Music: " Science Technology Background" by SFRecordsMusic