Who ruled New Orleans?

New Orleans sits on a bend of the Mississippi River about 160 kilometres above its mouth, on a strip of slightly raised ground between the river and Lake Pontchartrain. Whoever held the site controlled the trade of the whole Mississippi basin, which made it one of the most coveted ports in North America. Its history is defined by that strategic value, which passed it between France, Spain and the United States, and by a long struggle against water and disease on land that lies largely below sea level.

Before Europeans arrived, the lower Mississippi was home to peoples whose ancestors had built mound centres along the river for thousands of years, and in the early colonial era the Choctaw, Chitimacha and other nations lived and traded across the region. The city itself was founded in 1718 by Jean-Baptiste Le Moyne de Bienville for the French colony of Louisiana and named La Nouvelle-Orléans after Philippe, Duke of Orléans, then regent of France. John Law's Mississippi Company promoted the settlement, and by the early 1720s it had replaced Biloxi as the colony's capital. After a hurricane flattened most buildings in 1722, the engineers' grid plan was finally enforced; its streets survive as the French Quarter. Enslaved Africans, brought through the Atlantic slave trade, made up a large share of the population from the start.

At the end of the Seven Years' War, France secretly handed New Orleans and western Louisiana to Spain in the Treaty of Fontainebleau of 1762. Spanish rule took hold only after local colonists rose against the first governor in 1768 and were crushed the next year. Two great fires, in 1788 and 1794, destroyed most of the old wooden town, and the brick buildings with courtyards and iron balconies that replaced them give the "French" Quarter a largely Spanish-era look. The map's coarse dates blur what came next: Spain agreed to return Louisiana to France in 1800, but French officials took formal control only in November 1803, a few weeks before handing it over to the United States on 20 December 1803 under the Louisiana Purchase agreed with Napoleon.

In January 1815 Andrew Jackson's mixed force of regulars, militia, free men of colour and pirates defeated a British army at Chalmette, just downriver, in the Battle of New Orleans. Steamboats, cotton and sugar then made the city one of the richest in the country, and by 1840 it was among the largest. It was also the biggest slave market in the United States, where tens of thousands of people were sold to plantations further west. Yellow fever returned almost every summer, and the 1853 epidemic killed about 8,000 people.

Louisiana joined the Confederacy, but a Union fleet under David Farragut captured the city in April 1862, early in the American Civil War. Reconstruction brought brief political gains for Black citizens, followed by violent reaction and segregation; the challenge that led to the Supreme Court's Plessy v. Ferguson ruling of 1896 began with an arrest here in 1892. Around 1900 the city's Black and Creole musicians developed jazz, its most famous gift to the world.

In the twentieth century pumps and drainage canals allowed the city to spread over former swamp, but the land sank and the levees became its lifeline. When Hurricane Katrina struck on 29 August 2005, the floodwalls and levees failed in dozens of places and about 80 per cent of the city flooded. More than 1,800 people died across the Gulf Coast, most of them in Louisiana, and many residents never returned. Rebuilt behind a stronger flood-defence system, New Orleans today has about 360,000 people, and remains a major port and a centre of music, food and tourism.