Chicago (Zbigniew Bzdak / July 1, 2011)

1849: Spring storm sweeps away all Chicago River bridges.

1850: City planks 6.7 miles of streets, including 12,000 feet of State Street.

1851: Public Water Board organized to handle recurring cholera epidemics.

1852: First public transportation (a large horse-drawn carriage).

1853: YMCA expands to Chicago.

1854: Lakeview is promoted as a pleasant summer retreat away from city's disease and heat.

1855: Lager Beer Riots in April protest higher saloon taxes and anti-beer laws.

1855: Allan Pinkerton opens his detective agency

1856: City raises streets out of the swamp.

1856: Fort Dearborn is demolished.

1857: Allan Pinkerton's men thwart a grave-robbing scheme by a city official.

1858: Police force gets uniforms and fire department switches from volunteer to paid.

1859: First horse-drawn street railway, or horsecars, begins operation.

1860: Republicans meeting in the Wigwam nominate Abraham Lincoln for president.

1861: The Chicago Zouaves, Irish Brigade and Lincoln Rifles are among companies to march off to fight in Civil War.

1862: Camp Douglas converted to prison for rebel soldiers.

1863: First National Bank of Chicago founded.

1863: Rush Street bridge collapses, killing a girl and scores of cattle.

1864: Free mail delivery begins.

1865: Union Stock Yards open.