Visitors take selfies under a guideboard at the Hong Kong-Zhuhai-Macao Bridge on Friday. The world's longest cross-sea bridge opened on a trial basis on Friday for group tours. CHEN JIMIN/CHINA NEWS SERVICE

As a visitor who had just finished a tour of the Hong Kong-Zhuhai-Macao Bridge — the world's longest cross-sea bridge — on Friday, Yu Mei said she was impressed by both the beautiful bay scenery and the construction achievements of the bridge.

"As a former engineer, I was so impressed by the magnificence of this national super engineering project after gaining insights into its construction," said Yu, a resident of Zhuhai, Guangdong province, who admired the project on the first day of its trial tourism operation.

During the tour, Yu and other visitors completed a 140-minute escorted shuttle bus ride starting from the Zhuhai end of the bridge to the western artificial island, also known as Blue Dolphin Island.

Yu was one of the first 1,200 tourists to visit the bridge, she said, adding that she paid 188 yuan ($26.4) for her ticket.

According to the official WeChat account of the bridge tour, prior booking is required and can be done via WeChat, with ticket prices varying from 128 yuan to 298 yuan.

Tourists from the Chinese mainland with valid ID cards and those from the Hong Kong and Macao special administrative regions who have entered the mainland with valid travel permits are eligible to join the tour during the trial operation, according to Zhuhai Customs.

The bridge, with a length of 55 kilometers, opened to traffic in November 2018.

Conducting tourism activities on the bridge marks a historic breakthrough nationwide, as the route is located among the Hong Kong, Zhuhai and Macao ports, and within the Customs supervision zone and designated areas, said Zheng Shunchao, director of the administration bureau of the bridge.

"The bridge tour offers unique experiences different from regular sightseeing, as visitors can appreciate the magnificence of a national engineering project and experience the wonder of the bridge's construction," Zheng said.

During the tour, visitors also have the chance to admire wild Chinese white dolphins, known as the "giant pandas of the sea", as the tour route passes by the world's largest habitat of these dolphins.

"Though tourism will give new vitality to Blue Dolphin Island, it will also present challenges requiring additional maintenance and safety work," Zheng said.

With the trial operation, the director said the bureau will improve support facilities and services to provide a better visiting experience.

"We will enhance the role of the bridge as a new channel for economic and trade exchanges between Zhuhai, Hong Kong and Macao to facilitate the free flow of people, goods, capital, and innovation within the Guangdong-Hong Kong-Macao Greater Bay Area," said Huang Zhihao, the mayor of Zhuhai.