The Day America Topped Out the Tallest Structure on Earth
On December 6, 1884, workers set a 100-ounce pyramid of aluminum — then a precious metal — atop the Washington Monument, completing 36 years of work.
The most valuable thing atop the Washington Monument weighs about as much as a bag of sugar — and in 1884, it was worth a small fortune. On December 6 of that year, as cannons boomed and factory whistles screeched across Washington, D.C., engineers bolted a nine-inch pyramid of solid aluminum onto the monument's peak. At the time, aluminum was a precious metal, as costly as silver.
It had taken 36 years to get there. The monument to George Washington was begun in 1848, then stalled for more than two decades — seized by a nativist political faction, starved of funds, and interrupted by the Civil War. In the centennial year of 1876, Congress finally appropriated $200,000 to finish the job, and the Army Corps of Engineers, under Lieutenant Colonel Thomas Lincoln Casey, resumed construction in 1879, raising two-thirds of the great obelisk in just a few years.
The topping-out ceremony was pure 19th-century theater. On a breezy December 6, the 3,300-pound marble capstone was hoisted to the summit and set in place; then Casey himself placed the 100-ounce aluminum apex — the largest piece of cast aluminum ever made at the time, at $1.10 an ounce. The east face of the capstone, greeting the sunrise each morning, was inscribed with two Latin words: Laus Deo — "Praise be to God."
There was a delicious irony in the choice of metal. Within a couple of years, a new refining process made aluminum cheap and commonplace — the precious tip became ordinary kitchen metal. But in December 1884, nothing on Earth said "the future" quite like aluminum, and the monument's builders had crowned the Father of His Country with the wonder material of the age.
At 555 feet, the completed obelisk was the tallest man-made structure in the world — a title it held until the Eiffel Tower surpassed it five years later. It was formally dedicated on February 21, 1885, with President Chester Arthur declaring it "dedicated from this time forth to the immortal name and memory of George Washington." It remains the world's tallest stone obelisk.
Look closely at the monument and you can read its biography: the slight change in the marble's color partway up marks where construction stopped and restarted a generation later. And at the very top, that little aluminum pyramid still sits — a reminder that the future the builders imagined arrived faster than anyone expected, and that some bets on tomorrow pay off in the most literal way: set in stone.
Photo: Sadrulk, CC BY-SA 4.0 (via Wikimedia Commons).
