The suburbs of Washington, D.C., are jammed with housing developments, shopping centers, and endless miles of highway. But among the discount stores and tract housing are some delights that shouldn't be overlooked. They're easy to get to from either Baltimore or Annapolis and all are accessible from the Capital Beltway.

Among the gems are two homes connected with President Lincoln's assassination, the estate of one of Maryland's signers of the Declaration of Independence, and the home of the founder of the American Red Cross. You can visit farms and gardens, see jets and space ships, shop for antiques, and ride a roller coaster.

This guide has been divided according to the sites' locations around the Capital Beltway. But you don't always have to use the Beltway to get where you're going; plenty of other roads will get you there, too.

A new development, National Harbor, opened in 2009. A destination on its own, it's a great jumping-off spot for Washington, D.C., visitors, too.