Arguably the most magnificent building in Washington, the U.S. Capitol is where visitors go to witness politics in action. Inside, members of both houses of Congress debate and create national policy and law, while visitors explore the building's north and south wings and circular centerpiece: the Rotunda. This iconic hall houses paintings, frescoes and sculptures depicting famous scenes from American history, not to mention a 150-year-old cast iron dome.

Touring the Capitol is free of charge, but you'll need to make your reservation well in advance if you want to explore areas of the Capitol outside of the U.S. Capitol Visitor Center. The U.S. Capitol Visitor Center welcomes visitors Monday through Saturday from 8:30 a.m. to 4:30 p.m. (with the exception of Thanksgiving Day, Christmas Day, New Year's Day and Inauguration Day), and offers passes available on the day of your visit or online. If you wish to tour the Senate or House of Representatives galleries, you'll need to contact your senator or House representative’s office, respectively, to obtain free passes. If you're planning to visit during peak tourist seasons like spring and summer, same-day tour passes can be difficult to come by, so plan to make your reservations prior to your visit. Though some travelers express mixed reviews on whether the U.S. Capitol warrants the time and effort spent (both making reservations and going on the actual tour), most agree the site is well worth a visit.

If you're not that stoked about exploring the building's innards, consider taking a stroll (and a few photos) outside of the building. Thanks to the Capitol's prime location at the eastern end of the National Mall, you'll be afforded sweeping views of the Washington Monument and the Lincoln Memorial. The easiest way to reach the Capitol is off the Capitol South Metro stop (Blue, Silver and Orange lines) or the Union Station stop (Red Line). For more information, check out the official U.S. Capitol Visitor Center website.

After you've admired the Capitol, walk along East Capitol Street or through the Capitol's tunnel to the Library of Congress. Comprising three buildings and housing more than 164 million books, manuscripts, sound recordings, pieces of sheet music, maps and photographs, the Library of Congress holds the title of "largest library in the world." The most notable building in the trio is the Thomas Jefferson Building, which was built in 1897. Although you can't check books out (unless you've registered yourself as a researcher and obtained a Reader Identification Card), you'll find an eclectic array of interesting items, such as the Gutenberg Bible, as well as a rotating series of events and exhibitions. You should also take a stroll through the Thomas Jefferson Building's Main Reading Room, which features a grand domed ceiling, mahogany desks and diligent researchers pouring over catalogs and periodic volumes.

The Library of Congress is open to the public Monday through Saturday, though each building maintains different visiting hours. There are no entrance fees for this attraction, and free one-hour guided tours of the Thomas Jefferson Building are available Monday through Saturday. Events and exhibitions held at the Library of Congress are also complimentary for visitors. To find out more about the Library of Congress, visit the property's website.