A zoo enthusiast wears a mask of orangutan Redd on reopening day at Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

Giant panda Mei Xiang is reflected in a glass enclosure as visitors look up toward the trees where her cub Xiao Qi Ji was sleeping during the reopening morning of Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

Panda enthusiast Kate Huffer looks up into the trees to watch giant panda cub Xiao Qi Ji on reopening day of Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

Visitors take photos of giant panda Mei Xiang eating bamboo during the reopening morning of Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

Panda enthusiasts point their cameras up into the trees in an attempt to photograph panda cub Xiao Qi Ji on reopening day of Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

A visitor uses her phone to scan an entry ticket for the Asia Trail/Panda Pass on the reopening day of Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

A visitor takes a photo of giant panda Mei Xiang eating bamboo during the reopening morning of Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

A visitor takes a photo of giant panda Mei Xiang eating bamboo during the reopening morning of Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

Panda Mei Xiang plays with a toy during the reopening morning of Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

Panda enthusiasts point their cameras into the trees in an attempt to photograph panda cub Xiao Qi Ji on reopening day of Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

Panda cub Xiao Qi Ji hangs out in a tree on the reopening morning of Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

Panda enthusiast Jennifer shows off her panda tattoo on reopening day of Smithsonian's National Zoo in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

Panda enthusiast Amy Russian wears a panda theme face mask as she awaits the reopening of Smithsonian's National Zoo today in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

National Zoo enthusiasts Allen and Merry Richon hold hands as they enter the Asia Trail to see the pandas as Smithsonian's National Zoo reopened to visitors in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

National Zoo enthusiast Merry Richon wears a mask of a swamp monkey named Zawadi, one of over 300 handmade zoo themed masks she owns, as she awaits the reopening of Smithsonian's National Zoo today in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

National Zoo enthusiast Allen Richon wears a mask of the late Sumatran tiger Dumai, one of over 300 handmade zoo masks he owns, as he awaits the reopening of Smithsonian's National Zoo today in Washington, U.S., May 21, 2021. REUTERS/Kevin Lamarque

U.S. first lady Jill Biden views a cabin from a South Carolina slave plantation dating to the 1850’s during a brief tour as the museum reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden, with Secretary of the Smithsonian Lonnie Bunch and National Museum of African American History and Culture Director Kevin Young, views the Harriet Tubman exhibit during a brief tour as the museum reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden, with Secretary of the Smithsonian Lonnie Bunch and National Museum of African American History and Culture Director Kevin Young, takes a brief tour as the museum reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden, with Secretary of the Smithsonian Lonnie Bunch and National Museum of African American History and Culture Director Kevin Young, views the Harriet Tubman exhibit during a brief tour as the museum reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden, with Secretary of the Smithsonian Lonnie Bunch and National Museum of African American History and Culture Director Kevin Young, views the Harriet Tubman exhibit during a brief tour as the museum reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

Visitors and staff members gather to see U.S. first lady Jill Biden and Secretary of the Smithsonian Lonnie Bunch as the National Museum of African American History and Culture reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden, with Secretary of the Smithsonian Lonnie Bunch and National Museum of African American History and Culture Director Kevin Young, views a cabin from a slave plantation during a brief tour as the museum reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden, with Secretary of the Smithsonian Lonnie Bunch and National Museum of African American History and Culture Director Kevin Young, views a cabin from a slave plantation during a brief tour as the museum reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden greets National Museum of African American History and Culture Director Kevin Young and Secretary of the Smithsonian Lonnie Bunch as the museum reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden, with Secretary of the Smithsonian Lonnie Bunch, greets people as the National Museum of African American History and Culture reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden, with Secretary of the Smithsonian Lonnie Bunch, greets people as the National Museum of African American History and Culture reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden, with Secretary of the Smithsonian Lonnie Bunch, greets people as the National Museum of African American History and Culture reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden, with Secretary of the Smithsonian Lonnie Bunch, greets people as the National Museum of African American History and Culture reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

U.S. first lady Jill Biden, with Secretary of the Smithsonian Lonnie Bunch, visits the National Museum of African American History and Culture as it reopens to the public in Washington, U.S. May 14, 2021. REUTERS/Jonathan Ernst

The skeleton of a Tyrannosaurus rex, the large meat-eating dinosaur that lived in western North America and went extinct 66 million years ago, is displayed at the Smithsonian National Museum of Natural History in Washington, U.S. June 16, 2019. Picture taken June 16, 2019. REUTERS/Will Dunham

The Washington Monument and the Smithsonian Castle, as the sun sets in Washington, U.S., February 21, 2021. REUTERS/Al Drago

The Washington Monument and the Smithsonian Castle, as the sun sets in Washington, U.S., February 21, 2021. REUTERS/Al Drago

Scooter riders pass the Smithsonian museums, closed to tourists during the coronavirus disease (COVID-19) outbreak in Washington, U.S., May 22, 2020. Picture taken May 22, 2020. REUTERS/Jonathan Ernst

Scooter riders pass a construction zone at the Smithsonian museums, closed to tourists during the coronavirus disease (COVID-19) outbreak in Washington, U.S., May 22, 2020. Picture taken May 22, 2020. REUTERS/Jonathan Ernst

A view shows the horses of the Smithsonian Carousel, closed to tourists during the coronavirus disease (COVID-19) outbreak in Washington, U.S., May 22, 2020. Picture taken May 22, 2020. REUTERS/Jonathan Ernst

A view shows the horses of the Smithsonian Carousel, closed to tourists during the coronavirus disease (COVID-19) outbreak in Washington, U.S., May 22, 2020. Picture taken May 22, 2020. REUTERS/Jonathan Ernst

A view shows the horses of the Smithsonian Carousel, closed to tourists during the coronavirus disease (COVID-19) outbreak in Washington, U.S., May 22, 2020. Picture taken May 22, 2020. REUTERS/Jonathan Ernst

The horses of the Smithsonian Carousel, closed to tourists during the coronavirus disease (COVID-19) outbreak in Washington, U.S., May 22, 2020. Picture taken May 22, 2020. REUTERS/Jonathan Ernst

A closure note due to coronavirus disease (COVID-19) is seen at the entrance to the Washington Monument in Washington, U.S., March 14, 2020. REUTERS/Yuri Gripas

A closure note due to coronavirus disease (COVID-19) is seen at the entrance to the Washington Monument in Washington, U.S., March 14, 2020. REUTERS/Yuri Gripas

A closure note due to coronavirus disease (COVID-19) is seen at a ticket office to visit the Washington Monument in Washington, U.S., March 14, 2020. REUTERS/Yuri Gripas

Closure notes due to coronavirus disease (COVID-19) are seen at the National Museum of American History in Washington, U.S., March 14, 2020. REUTERS/Yuri Gripas

A closure note due to coronavirus disease (COVID-19) is seen at the National Museum of American History in Washington, U.S., March 14, 2020. REUTERS/Yuri Gripas

U.S. National Park Service ranger stands next to a closure note due to coronavirus disease (COVID-19) at the Washington Monument in Washington, U.S., March 14, 2020. REUTERS/Yuri Gripas

62nd Grammy Awards - Show - Los Angeles, California, U.S., January 26, 2020 - Jeff Place & Robert Santelli, compilation producers and Pete Reiniger, mastering engineer, accept the award for Best Historical Album for "Pete Seeger: The Smithsonian Folkways Collection." REUTERS/Mario Anzuoni

People enter the Smithsonian subway station by the National Mall in Washington, U.S., November 22, 2019. REUTERS/Loren Elliott

Bei Bei, the giant panda, is seen for the last time at the Smithsonian National Zoo, before his departure to China, in Washington, U.S., November 19, 2019. REUTERS/Yara Nardi

Bei Bei, the giant panda, is seen for the last time at the Smithsonian National Zoo, before his departure to China, in Washington, U.S., November 19, 2019. REUTERS/Yara Nardi

Bei Bei, the giant panda, is seen for the last time at the Smithsonian National Zoo, before his departure to China, in Washington, U.S., November 19, 2019. REUTERS/Yara Nardi

Bei Bei, the giant panda, is seen for the last time at the Smithsonian National Zoo, before his departure to China, in Washington, U.S., November 19, 2019. REUTERS/Yara Nardi

Bei Bei, the giant panda, is seen for the last time at the Smithsonian National Zoo, before his departure to China, in Washington, U.S., November 19, 2019. REUTERS/Yara Nardi

Bei Bei, the giant panda, is seen for the last time at the Smithsonian National Zoo, before his departure to China, in Washington, U.S., November 19, 2019. REUTERS/Yara Nardi

Bei Bei, the giant panda, is seen for the last time at the Smithsonian National Zoo, before his departure to China, in Washington, U.S., November 19, 2019. REUTERS/Yara Nardi

Bei Bei, the giant panda, is seen for the last time at the Smithsonian National Zoo, before his departure to China, in Washington, U.S., November 19, 2019. REUTERS/Yara Nardi

Workers look at a FedEx's crate where Bei Bei, the giant panda, has been placed before his departure to China, at the Smithsonian National Zoo, in Washington, U.S., November 19, 2019. REUTERS/Yara Nardi

Bei Bei, the giant panda, is seen for the last time at the Smithsonian National Zoo before his departure to China, in Washington, U.S., November 19, 2019. REUTERS/Yara Nardi

Visitors walk past the largest mounted specimen of the African Bush Elephant believed to be the world's largest living land animal, at the Smithsonian National Museum of Natural History in Washignton, November 1, 2019. Picture taken with a slow shutter speed. REUTERS/Siphiwe Sibeko

Kylie Zimmerman from the Smithsonian Institute packs corals delivered to her by Karen Neely, a coral ecologist at Nova Southeastern University, to take back to a lab to study the histology of Stony Tissue Loss Disease (SCTLD) near Key West, Florida, U.S. September 9, 2019. REUTERS/Lucas Jackson SEARCH "JACKSON CORAL" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Kylie Zimmerman from the Smithsonian Institute watches as PhD students Bradley Weiler (R) and Anthony Bonacolta take samples to study from corals afflicted by Stony Tissue Loss Disease (SCTLD) near Key West, Florida, U.S. September 9, 2019. REUTERS/Lucas Jackson SEARCH "JACKSON CORAL" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.