Crowds flocked to the National Zoo in Northwest Washington over the weekend to bid their final goodbyes to Bei Bei, the giant panda cub, as he prepares to leave the only home he has known for China.

Zoo officials have had a week of special activities for humans at the zoo — along with frozen fruit cakes for Bei Bei — as keepers prepare to fly the 240-pound panda to China on Tuesday as part of a deal between the two countries. China owns all giant pandas and leases them to U.S. zoos; they have to go to China when they turn 4 so they can be bred.

Bei Bei was born at the zoo in 2015 and is the last of the zoo’s three giant panda cubs to go. His name means “precious treasure.”

His leaving comes at a time of uncertainty for pandas at the zoo, where they have been a nearly constant — and popular — attraction for the last 47 years.

Mei Xiang, his mother, had a “false pregnancy,” where female pandas can show signs of being pregnant but aren’t really pregnant, in March. That followed two other false pregnancies in the last few years.

For now, it’s not known whether the zoo will get any new giant panda cubs. And it’s also unclear whether China will want back Mei Xiang and Bei Bei’s father Tian Tian, who were both born in China and have been on a long-term leases to the United States. Their lease expires next year on Dec. 7.

Bei Bei is the third giant panda to have been born at the zoo and moved to China. Tai Shan moved in 2010, and Bao Bao moved in 2017.

A week of events has marked Bei Bei’s imminent departure. Visitors over the weekend were served dumplings, courtesy of the Chinese Embassy. In turn, they wrote postcards and made friendship bracelets for the panda.

Bei Bei got treats, too, including ice cakes filled with frozen juice, sweet potato and sugar cane.

Over the last week, the zoo has been putting up messages on its social media accounts that read like a walk down memory lane of Bei Bei’s four years at the facility, using the hashtag #ByeByeBeiBei. It has shared the first ultrasound showing the panda and images of the cub playing in the snow at his enclosure.

The zoo shared that pandas spend 10 to 16 hours a day eating about 20 to 40 pounds of bamboo each day. Some might be surprised to know that although pandas may look fluffy, their fur is “very coarse and dense like wool,” the zoo said on Twitter. That fur “acts as a cushion when cubs tumble and fall.”

There have also been some reminders of how cute and entertaining Bei Bei has been. One video from the panda cam at his exhibit showed Bei Bei doing two of his favorite things: climbing and tumbling.

The zoo also encouraged panda fans to make a mix tape of music that the panda might want to listen to on his long flight to China.

Over the weekend, zoo officials said they saw an uptick in visitors, with more than 12,700 coming Saturday and Sunday, compared with 5,500 during the same weekend in 2018. Some visitors this weekend came from Massachusetts, Ohio, Pennsylvania, West Virginia, Florida, New York and New Jersey, according to zoo officials.

On Tuesday morning, Bei Bei will be taken from his enclosure at the zoo and put in a crate and driven to Dulles International Airport, where he’ll be put on a FedEx plane with keepers for a 16-hour nonstop flight to China.

Zookeepers said Bei Bei was doing well on Monday, and they were “sticking to his regular schedule” through Tuesday morning. He has been training with his keepers the last few weeks on getting into — and staying in — the crate. A spokeswoman for the zoo said his crate training has “gone very well and easily.”

Pamela Baker-Masson, a spokeswoman for the zoo, said Monday in an email that “Bei Bei willingly goes into the crate, enjoys his treats,” and “is comfortable with the doors closed.”

Zoo officials said that once they get Bei Bei off, they’ll focus on an agreement with the Chinese in 2020 regarding pandas.

“Bei Bei is just one of many conservation successes,” Baker-Masson said. “There is still a lot of conservation work to be done and for all the right and important reasons, we want to continue our giant panda program.”