The Chicago "L" elevated rail system begins operation.

The Chicago "L" is the rapid transit system serving the city of Chicago and some of its surrounding suburbs in the U.S. state of Illinois. Operated by the Chicago Transit Authority (CTA), it is the fourth-largest rapid transit system in the United States in terms of total route length, at 102.8 miles (165.4 km) long as of 2014, and the third-busiest rapid transit system in the United States after the New York City Subway and the Washington Metro. As of January 2024, the "L" had 1,480 rail cars operating across eight different routes on 224.1 miles of track. CTA trains make about 1,888 trips each day servicing 146 train stations. In 2024, the system had 127,463,400 rides, or about 360,100 per weekday in the first quarter of 2025.

June 6 is the 157th day of the year in the Gregorian calendar; 208 days remain until the end of the year.