WASHINGTON - You may think of the National Mall or the C&O Canal as a nice place to have lunch or spend a quiet Sunday afternoon, but those locations are also part of some big business for the National Capitol Region.

National parks in D.C., Maryland and Virginia generated more than $1.8 billion in revenue in 2010 from 58 million visitors and supported more than 22,000 related jobs.

National Parks Service Spokesman Bill Line says that includes spending on all kinds of things.

"Hotels, restaurants, souvenirs, books, photography items, taxi cabs, pedi-cabs," he says....