Although she had traveled to many places, she has not yet visited Aleppo in Syria-where the earliest soap in the world was produced-due to conflict there. Chen displays a small soap sculpture of a destroyed house in Syria made by herself, hoping that she will visit Aleppo when there's peace in the city.

"As long as there is an interesting thing about soap, I will go," Chen says.

When most visitors gathered to view Mona Lisa by Leonardo da Vinci at the Louvre Museum in Paris, Chen went directly to see The Death of Marat by Jacques-Louis David, which features Marat, a leader of the French Revolution of 1789, dead in his bathtub. Or, when tourists in Rome thronged the Colosseum, she visited the Baths of Caracalla to find out the bath culture, which fascinates her as much as soap.

Different countries have different bath cultures. In ancient Rome, people regarded the thermae (bathing houses) as a social place, where they could read books and go shopping. In ancient China, bath was a private thing. "In ancient Chinese residences, there's seldom a bathroom," says Chen.

Traveling to so many places to gather soaps costs Chen a lot. She says she has invested millions of yuan on collecting soap. The traveling itself accounts for much of her expenses.

"My soap collection has opened a new world for me. It's like a new chapter of my life," says Chen, who does part-time soap-crafting by hand.

In 2008, Chen was troubled by a skin problem caused by pimples, which made her feel "inferior". A soap sent by her sister happened to solve her skin problem. From then on she began buying soaps in large quantity and kept buying for more than a decade.