On May 3, 1971, at 5 p.m., All Things Considered debuted on 90 public radio stations.

In the more than four decades since, almost everything about the program has changed, from the hosts, producers, editors and reporters to the length of the program, the equipment used and even the audience.

However there is one thing that remains the same: each show consists of the biggest stories of the day, thoughtful commentaries, insightful features on the quirky and the mainstream in arts and life, music and entertainment, all brought alive through sound.

All Things Considered is the most listened-to, afternoon drive-time, news radio program in the country. Every weekday the two-hour show is hosted by Ailsa Chang, Audie Cornish, Mary Louise Kelly, and Ari Shapiro. In 1977, ATC expanded to seven days a week with a one-hour show on Saturdays and Sundays, which is hosted by Michel Martin.