The NASA Extreme Environment Mission Operations (NEEMO) 21 mission began on July 21 as an international crew of aquanauts splashed down to the undersea Aquarius Reef Base, located 62 feet below the surface of the Atlantic Ocean in the Florida Keys National Marine Sanctuary. The NEEMO 21 crew will perform research both inside and outside the habitat during a 16-day simulated space mission. During simulated spacewalks carried out underwater, they will evaluate tools and mission operation techniques that could be used in future space missions, including journeys to Mars. (Photo by Karl Shreeves/NASA)

In this photo provided by the Florida Keys News Bureau, female impersonator Gary Marion, known as “Sushi”, sits in a large replica of a women's high-heel shoe while dangling above Duval Street, late Tuesday, December 31, 2019, in Key West, Fla. The Red Shoe Drop is one of six offbeat Key West warm-weather takeoffs on New York City's Times Square “ball drop” set to celebrate the beginning of 2020. (Photo by Andy Newman/Florida Keys News Bureau via AP Photo)

Frida Karlsson takes 2nd place, Therese Johaug of Norway takes 1st place, Ingvild Flugstad Oestberg of Norway takes 3rd place during the FIS Nordic World Ski Championships Women's Cross Country Classic on February 26, 2019 in Seefeld, Austria. (Photo by Lisi Niesner/Reuters)

Rian Johnson, left, director of the upcoming film “Knives Out”, takes a picture of cast member Ana de Armas as they are introduced onstage during the Lionsgate presentation at CinemaCon 2019, the official convention of the National Association of Theatre Owners (NATO) at Caesars Palace, Thursday, April 4, 2019, in Las Vegas. (Photo by Chris Pizzello/Invision/AP Photo)

A country music fan cools off in the wind on the second day of the Stagecoach country music festival in Indio, California April 26, 2014. (Photo by Mike Blake/Reuters)

The National September 11 Memorial & Museum (branded as 9/11 Memorial and 9/11 Memorial Museum) is the principal memorial and museum commemorating the September 11 attacks of 2001, which killed nearly 3,000 people, and the World Trade Center bombing of 1993, which killed six. The memorial is located at the World Trade Center site, on the former location of the Twin Towers, which were destroyed during the attacks. The World Trade Center Memorial Foundation was renamed the National September 11 Memorial & Museum at the World Trade Center in 2007.

“Aurora Hunters”. Photographers taking part in a photography tour on the Lofoten Islands in Norway, pull over on the side of the road to take a photo of their first ever Aurora Borealis after spotting it from their tour bus. Photo location: Rystad, Lofoten Islands, Norway. (Photo and caption by Mark Gee/National Geographic Photo Contest)

A sticker is seen at the Rocky Mountain Guns and Ammo store in Parker, Colorado July 24, 2012. The killing of 12 people at a midnight screening of the new Batman movie in the Denver suburb of Aurora may spark a fresh round of soul-searching on America's relationship with guns but few predict any real change in the law. (Photo by Shannon Stapleton/Reuters)