Thaddeus Kosciuszko National Memorial

Thaddeus Kosciuszko was the commander of the Polish Army, a Revolutionary War hero, a military engineer, and statesman of the Polish-Lithuanian Commonwealth. After leading a rebellion against Russia in 1794, he was imprisoned for several years and left the country upon his release, first to England, then to the United States. 

When Kosciuszko arrived in Philadelphia in 1797, he was greeted by cannon salutes and given a hero's welcome—he had been a brigadier general in the Revolutionary War. Wounded and without funds, he was put up in the boarding house of Ann Rief, which was, at the time, the smallest and cheapest place his secretary could find.

He met with many notable people in his lodgings, including Thomas Jefferson (who was the executor of his will), Chief Joseph Brant, and Benjamin Rush. Kosciuszko recuperated from his wounds, hoping to join Napoleon in his fight against the Russians. He passed the time playing chess, and discussing science, painting portraits, and writing letters back to Europe, all the while rarely leaving the house or his bedroom (which is preserved to this day).

The following year he left for France, departing in the middle of the night with little warning. He was considered by some to be a possible French spy, and there were rumors of a possible deportation had he not left. Kosciuszko was an informal envoy from France to Jefferson but held no official diplomatic role. He died in 1817 in Switzerland, having never returned to his native Poland. 

Today the house in Philadelphia stands as a memorial to Kosciuszko. It was built in 1775, and by the 1970s, was in a state of neglect. A Polish-American businessman donated the house to the U.S. government, and it became a National Monument in 1972. It is the smallest National Park unit in the United States at 0.02 acres or 80 square meters.