Penn Quarter & Downtown

Those eight columns look like marble, but they're a magnificent lie — brick, plastered and hand-painted to fake the veining, and they're among the largest Corinthian columns on earth. Montgomery Meigs, the Army engineer who designed this place, was obsessed with airflow for the wounded Civil War veterans who'd climb these stairs for their pensions, so look closely at the upper walls: he left deliberate gaps between the brackets, missing bricks that let breezes move through 15 million of them. The whole building breathes. Grover Cleveland danced his inaugural ball here in 1885 while it was still a construction site, and seven presidents have followed him onto this floor. Most days you'll have the place nearly to yourself, your footsteps booming up into that 159-foot ceiling like a phantom regiment marching. Here's the thing tourists miss: you don't need a ticket to stand in the Great Hall — it's free to walk in and gawk. Buy the museum admission only if the exhibit galleries off the sides tempt you. Grab a coffee from the café and just sit a while.