Giant pandas are some of the world's most vulnerable and rare creatures. The United States has the most giant pandas outside China. [Photo provided to China Daily]

The bestowment of two giant pandas on the US in 1972 began the 'year of the panda' and a continuing fascination with the rare and vulnerable animals

A green-hued April day, 19-month-old giant panda cub Bei Bei was climbing a tree at the National Zoo in Washington D.C., the United States, drawing laughter from the crowds.

"I started coming here way back to the 1970s when China gifted two (giant) pandas to Washington," Stephanie Smith, gray hair with a panda hat pin, was overjoyed by every move of Bei Bei at the giant panda house.

Smith is just one of the two million panda fans home and abroad coming to Washington to see giant pandas every year.

"They are just part of Washington like our First Family," said Smith. "They are such peaceful, wise creatures."

It was also an April day 45 years ago, when Ling Ling and Hsing Hsing, carefully selected and given by the Chinese government as a gift to commemorate the groundbreaking handshakes between leaders from China and the United States that year, arrived at Washington, welcomed by around 8,000 Americans in the rain.

It was the first time that the Chinese government gave giant pandas as a gift to a Western country. The New York Times put it as front page news, saying that "zoo directors are bringing every kind of pressure to get one of the furry clowns with the black-patched white bodies and the black-ringed eyes."

The debut of Ling Ling and Hsing Hsing at the National Zoo attracted more than 20,000 people far and wide and the number of visitors for the first month was as many as 110,000, arousing not only Panda-mania across the country, but also interest in China among the American people.

The year of 1972 was marked as "the year of the panda" in the United States with "panda diplomacy" bringing closer the peoples from both sides of the Pacific Ocean. For four decades since then, giant pandas have remained a symbol of friendship between the two countries.

US-born giant panda Bao Bao met the public for the first time in Chengdu in southwest China's Sichuan province on March 24, a month after the 3-year-old female flew back to her home country on a charter flight from Washington.

US Charge d'affaires David H. Rank told Xinhua after watching Bao Bao settling in her home that he thought the day meant so much to the cooperation between the US and China, praising the cooperation between the two countries on scientific research and protection of endangered wildlife.

During her 16-hour trip to Chengdu, Bao Bao was accompanied by her American keeper Marty Dearie and Dr Katharine Hope to ensure a smooth flight. She was greeted by Chinese experts immediately after landing at the Chengdu Shuangliu International Airport on Feb 22.

"Upon arrival at the Dujiangyan panda base, Bao Bao walked into her new enclosure within one minute when her new keeper opened her travel crate door. She immediately started exploring and was very relaxed," Dearie wrote on the website of the US National Zoo.