NASA asked. 56,000 votes decided.

In honor of Earth Day's 50th anniversary and the 20th anniversary of NASA's Earth Observatory, the space agency invited the public to vote on the best pictures that capture our beautiful planet in the Earth Observatorys collection. (The Earth Observatory is a publishing outlet where NASA shares images and other discoveries that come from its research.)

After five rounds of voting, the winner of Tournament Earth was announced on April 28.

The winning photo, taken in 2001 by Serge Andrefouet, a remote sensing specialist at the University of South Florida, captures sand and seaweed in the Bahamas using the Landsat 7 satellite. Tides and ocean currents created the patterns you can see in the image.

Check out the winner (and some of the other finalists) below.

WINNER! This year's winning image was also a runner-up in the 10th anniversary contest.

RUNNER-UP: Astronauts captured a volcanic plume in the Raikoke Volcano, a volcano on the Kuril Islands that doesn't often erupt.

FINAL ROUND: Captured on Landsat 8, this image shows the transition from sand dunes to land in southern Africas Namib Desert.

FINAL ROUND: This image, a combination of art and scientific imaging, was made using data from satellite missions, with graphic artists creating layers of global data for things like land surface and sea ice layers.

THIRD ROUND: At the International Space Station, astronauts captured "aurora australis" (the southern lights) with a digital camera while above the Indian Ocean.

THIRD ROUND: This, of course, isn't a picture of Earth at all. It's an image of Saturn taken from the Cassini spacecraft, but Earth Observatory liked it enough to include it. (Technically, you can see Earth in the upper left quadrant of Saturn's rings.)

THIRD ROUND: One of a series of images documenting Alaska's Columbia glacier, this image tracks the glacier's fast-moving retreat.

THIRD ROUND: Astronauts took a picture with a digital camera ofAtafu Atoll, the smallest of three atolls and one island making up theTokelau Islands in the southern Pacific Ocean. (Atafu Atoll is about eight kilometers wide!)

Landsat 8 caught an ongoing eruption flowing in Iceland betweenthe Bardarbunga and Askja volcanoes.

The image here captures the melting ice cap on Eagle Island in Antarctica as it hit its hottest temperature on record this February.

A NASA camera on the Deep Space Climate Observatory caught the moon as it passed between the spacecraft and Earth.

With a new instrument available on the International Space Station since 2014, scientists now hope to observe some of the 4.3 millionlightning flashes that occur daily. Here are just some of them.

Taken from Voyager 1, this image from 1977 shows the Earth and Moon together back when Voyager 1 was a mere 7.25 million miles from Earth. (As of 2012, it was 11.31 billion miles from Earth.)

This image is a visualization of the solid particles and liquid droplets (called aerosols) found in ecosystems around the world on just one day: August 23, 2018.

This picture of the Andaman Sea was captured by Landsat 8, which, thanks to the reflection of the Sun, makes internal waves readily visible.

A tried and true favorite, this iconic 1968 photo was taken by the Apollo 8 crew while orbiting the Moon.

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NASA releases the winning photos of Tournament Earth - Mashable