Archives-Navy Memorial Metro. Research access will not be affected. In a city of monumental architecture where even its 72 columns barely raise an eyebrow, its most distinctive feature is the bronze doors at the Constitution Avenue entrance. Each weighs six and a half tons and is 38 feet high and 11 inches wide. Though security is their main function, they also remind the visitor of the importance of the contents.
Cathedral doors spring to mind.
Unless you're a history junkie, skip the dull tour, which basically consists of a guide displaying copies of the various documents held in the stacks. Cut straight to the main attraction. Each sheet of parchment is enclosed in a sealed case containing only helium and water vapour. The documents have a green tinge, thanks to UV filters - as the staffer stationed nearby explains every other minute to the reverential line of visitors shuffling past. For the record, the handwriting on the Declaration of Independence isn't Jefferson's - it was transcribed by Timothy Matlack, an otherwise anonymous clerk.