Your walk begins at the southern tip of Manhattan, where the island meets New York Harbor. The Dutch West India Company built Fort Amsterdam here in 1626 on a narrow point the Lenape called Mannahatta, the island of many hills. The British took it in 1664 without a shot, renamed it Fort James, then Fort George, and expanded the battery of cannon that gave this park its name.
Castle Clinton, the round sandstone fort before you, was built between 1808 and 1811 to guard the harbor against the British again, but the war ended before it was tested. It served instead as a concert hall where Jenny Lind performed, then an immigration station processing eight million people between 1855 and 1890, then a public aquarium for half a century. Find the Statue of Liberty across the harbor, exactly where you're looking now; she arrived in 1886, a gift from France, her torch marking where generations of immigrants first saw land.