WHAT: Tour Washington at night on a bike. The nation's capital is austere in a way it is not during the day, under the glare of the sun. As the sky turns from blue to purple and finally black, Jefferson seems to stand taller, Lincoln to clench his fist tighter, the Vietnam Veterans Memorial to sink lower. The Bike and Roll Sites tour starts behind the Old Post Office and hits many of the hot spots on the Mall, from the World War II Memorial down to the Lincoln Memorial, through West Potomac Park to the Jefferson Memorial.

Bikes have lights; riders wear reflective vests. The tour stays on sidewalks. The Trek bikes are new every year and come with a water bottle and helmet. Trailer carriers are available for young kids. One guide rides in the front of the group and one in the back; safety is their biggest concern, said our tour guide, Jas Guram, 24.

The tour reflects on the beauty of the city's night sky and helps you bone up on D.C. facts such as why it is that you can view the White House from the Jefferson Memorial. The guide talks about every important place before cyclists look around.

One of the best things about the bike tour is its efficiency.

"It would take two or three days to do all the stuff we did in a couple hours," Matthew Dalimonte, 12, said after the tour. Visiting from Massachusetts with his mom, dad and two younger brothers, Matthew said the bike tour was one of his favorite activities.

IF YOU GO: The Bike and Roll tour is four easy and slow miles, round trip, with a maximum of 15 riders per trip. You can leave bags at the meeting place. Another tip: Bring bug spray; you may have to bike through whole clusters of mosquitoes cruising next to the Potomac River en route to see Mr. Jefferson.

COST: Adults, $45, kids 12 and younger, $35. Tours run 6:30-9:30 p.m. daily except Wednesdays.

MEET: Federal Triangle Metro station, 302 12th St. NW. Behind the Old Post Office. Arrive early to get set up with your bike.

WHERE TO EAT: Grab a drink or a late-night bite at Old Ebbitt Grill, 675 15th St. NW. Food is served until 2 a.m.

202-842-2453, www.bikeandroll.com.