Underneath downtown Oklahoma City’s skyscrapers, a Chinese restaurant has been serving businessmen and women for years.

Nan Lay and her husband — she is from Cambodia and he is from China — have owned China Chef in The Underground for the last 20 years, and all of their business has come through word of mouth. The Underground is a series of tunnels connecting office buildings and parking lots and is only open from 6 a.m. to 8 p.m. Monday through Friday, with the primary function of getting people from their cars to their offices. Including China Chef, there are a handful of restaurants along the tunnels.

The time constraints are an issue for Lay, though. Since The Underground mainly serves business people, China Chef is only open for lunch on the week days, making it hard for her and her husband to grow their business. They are also limited by the amount of space they have.

“We cannot grow any bigger because of the space limit,” Lay said. “So somedays we’re really busy, somedays OK, somedays I wish I had more customers. But somedays I wish I had more seats for the customers, but it’s OK”

Despite the challenges, Lay said she and her husband are happy in The Underground and enjoy having their business there — that’s what has kept them there for so long.