The Pacific Exchange: China & US Mail exhibition opens in Washington on March 20, 2014. [Photo/ CRI online]

Some highlights among the 175 items are an 1849 letter sent from Boston took nearly 3 months to reach an American opium trader in Guangzhou and several stamps made by the China Bureau of Engraving and Printing in 1912 that survived a fire. Visitors could also find the first Chinese Lunar New Year Stamp issued by the US Postal Service – a black and white rooster stamp.

Visitors observe the collection really keenly. Some even hold a magnifying glass in order to study the intricate details of each stamp.

William Stap is one of them. He says the exhibition helps him to better understand Chinese history and culture.

"I really enjoy the exhibition. The stamps are beautiful, they really are. It's fascinating to look at history through stamps and see what they have to tell us. It's not complete, but it's an engaging way to do it. Because almost everybody loves stamps."