A visitor takes a selfie at a photo exhibition featuring Shanghai-Houston sister city ties in Houston, the United States, July 17, 2019. (Xinhua/liu Liwei)

HOUSTON, July 17 (Xinhua) -- An exhibition of more than 300 photos featuring Shanghai-Houston sister city ties kicked off here Wednesday, in commemoration of the 40th anniversary of the establishment of China-U.S. diplomatic relations.

The three-day exhibition, themed "Trans-Pacific Exchange and Cooperation -- Shanghai Commemorates the 40th Anniversary of China-U.S. Diplomatic Relations," highlights stories of cultural exchanges, economic cooperation and friendship between the two peoples, as well as state visits and exchanges between officials of the two sides.

The photos are segmented into five sections with sub-themes, including "having friends coming from afar," "mutually beneficial and win-win economic and trade cooperation," and "rich and diverse cultural exchange."

So far, Shanghai, China's financial center and a key window to observe the country's reform and opening-up, has established sister-city relations with San Francisco, Chicago and Houston.

Paul Sheard, president of Tempe Sister Cities, a non-profit organization in the city of Tempe, Arizona, told Xinhua that the exhibition was "informative and very interesting" and "conveys the message that it's a real strong partnership" between Shanghai and its sister cities.

Sheard said he was impressed by Tesla's gigafactory being built in Shanghai. "So I think it really exhibits the fact that the relationship is so strong especially in today's world."

The Tesla factory, with an investment of over 50 billion yuan, is the largest foreign-invested manufacturing project in Shanghai's history, and Tesla's first outside the United States.

Shanghai's trade volume in goods with the United States surged to 16 percent of the city's international trade volume in aggregate in 2018, a remarkable rise from the merely 4.5 percent back in 1979, when China and the U.S. established diplomatic ties, according to official statistics.

At present, there are more than 4,000 U.S. companies operating in Shanghai among the 50,000 foreign-invested firms in the city. The regional headquarters, research and development centers built by U.S. firms accounted for 28 percent and 26 percent respectively of the city's totals.