When it was finished in 1884, this monument was the tallest structure in the world, holding that title for five years until it was surpassed by the Eiffel Tower in Paris. Even today, no building in Washington, District of Columbia is allowed to overtop it due to local building height restrictions. The monument is capped by an 8 inch pyramid of aluminum. At the time it was placed, aluminum was as rare and precious as silver; it was the largest single piece of cast aluminum ever made up to that point. On the east face of that capstone, hidden from view but facing the rising sun, are the Latin words ‘Laus Deo,’ which translate to ‘Praise be to God.’ Because the structure is made entirely of stone blocks held together by gravity and friction—with no steel rebar—it is incredibly heavy, weighing over 81,000 tons. Yet, even in 30 mile-per-hour winds, the peak sways just one-eighth of an inch, a testament to the engineering genius of the United States Army Corps of Engineers.