Sienna Stoneking, a freshman at Muscatine High School in the US state of Iowa, could not conceal her excitement when recalling her first trip to China, which she made last month with the encouragement of President Xi Jinping.

"If anyone is thinking of taking a trip there, it's a once-in-a-lifetime opportunity, and go for it!" she said.

More than 20 students from the high school, including Stoneking, participated in an exchange visit to Beijing, Shanghai and Hebei province from Jan 24 to 30.

After wrapping up their tour of China, the students wrote a letter to Xi, sharing their joy during the trip and thanking him for the invitation.

"More than ever now, this trip motivated me to take a deeper dive into the culture, and someday I hope to become fluent (in Mandarin) and take many more trips," Stoneking said.

Xi replied to the young US visitors on Saturday, the Chinese Lantern Festival, which marked the first full moon of the Year of the Dragon. Xi also sent them New Year cards.

In his reply, Xi noted that Lantern Festival has long been an important moment for the Chinese people to express their hope for a better life.

He extended holiday wishes to the teachers and students of the school, and encouraged more US youths to come to China for exchanges and study.

The young visitors became the first group of United States high school students to visit China under a program that aims to invite 50,000 young people from the US to go to China in the next five years for exchanges and study. Xi announced the program in San Francisco in November during his visit to the US.

Xi welcomed the school's students to be part of the program when he replied last month to Sarah Lande, one of his "old friends" from Iowa. Lande had hosted Xi in the Iowa city of Muscatine when Xi first visited the US in 1985 as a county-level official from Hebei province.

When the US students arrived in Beijing, one of their gifts to Xi was a school flag written with Chinese characters that said "Grandpa Xi, here we are".

The students' letter addressed to Xi featured beautifully written Chinese characters as well as vividly hand-painted dragon, Great Wall and giant panda depictions.

In his reply on Saturday, Xi said he was happy that the students had visited several Chinese cities, where they saw pandas, tasted Chinese delicacies, experienced Chinese culture and had a lot of fun.

Learning that the US students had made many Chinese friends during the trip and had invited them to visit their hometown in the US, Xi said he was touched by their friendship.

Stoneking told China Daily: "I feel honored to have the opportunity to communicate with President Xi Jinping. It's still so shocking to me the connection we share with China."

She added that she and a classmate "agreed that if we were given the chance to go to college there, we would take a plane in a heartbeat".

Dan Stein, chairman of the Muscatine-China Initiatives Committee and a native of Muscatine, accompanied the students for much of the China trip.

"It was the first time for the students to leave the United States or, for a lot of them, even to travel on an airplane," he said.

"It's one thing to see in a video or on TV about another country. But to go there firsthand and taste the food and see the sights and smell the air, feel the culture, I think that was what the trip accomplished," he said.

"I'm hopeful that we can continue to have more exchanges. And at the same time, we want more Chinese people to also come visit us in the US so they can see the same thing and feel it firsthand," he added.

'Seeing is believing'

In 1985, Xi visited Muscatine as secretary of the Communist Party of China Zhengding county committee in Hebei province.

In his reply letter on Saturday, Xi cited a Chinese saying that "seeing is believing", noting that the warm and friendly people he met in the US in 1985 left an indelible impression.

Likewise, it is believed that through this exchange visit, the students can gain a more intuitive and in-depth understanding of China and the Chinese people, Xi said.

Xi encouraged the Muscatine High School students to revisit China, and he encouraged more young people from the US to come to China for exchanges and study.

He added that they can get firsthand experience of the real China in a multidimensional and comprehensive manner, foster genuine friendship with Chinese youths, and learn from one another so that they can jointly contribute to a stronger friendship between the people of the two countries.

The students visited Beijing Zoo to see giant pandas and listened to briefings about wildlife protection. While in Beijing, they also joined local high school students at a cultural experience center to learn about traditional Chinese medicine and the evolution of Chinese characters, and they tried on Peking Opera costumes.

During their trip to Shijia-zhuang, the provincial capital of Hebei, they toured Shijiazhuang Foreign Language School, tried the Chinese folk art of paper-cutting, and made dumplings together with their Chinese peers.

"All of the facilities that they had at the school were really great. In the US, we have a lot of opportunities, but here there were so many sports and extracurriculars," said Arabella Fourneau, another freshman at Muscatine High School.

"The city was amazing, and the people were so friendly to us," she added.

In Shanghai, the students explored the city with local teenagers, tried calligraphy, visited Fudan University for a photo exhibition about China-US exchanges, and toured the Shanghai Tower skyscraper for a bird's-eye view of the Lujiazui financial district.

"It's just opening up channels of communication," said Aaron Smith, a teacher at Muscatine High School. "Like right now, I'm having conversations with faculty members that I met, with some students that I met, just sharing ideas.

"When you have these open channels of communications, it just strengthens the line of friendships," Smith added.

Apollo Haye, a junior at Muscatine High School, said: "China was a beautiful place, and I was stunned by the history and modern advances they had. The architecture and art were amazing. I would like to study more on China after returning from this trip, and I hope to get into an exchange program for it."

Stein, the chairman of the Muscatine-China Initiatives Committee, said the trip was "a life-changing experience" for the young visitors.

"I think they're more open and more interested in China. They want to know more and meet more Chinese people. Overall, the trip met the vision of President Xi that he laid out in San Francisco to get people to actually come and see," Stein added.