The longest recorded concert lasted 18 days
In 1932, Austrian composer Franz Lehár organized a concert marathon in Berlin to raise funds for the city's unemployed. The event, which became known as the "18-Day Concert," featured a rotating cast of musicians and performers, with over 1,000 participants taking the stage at some point during the marathon. The concert finally came to a close on March 8, 1932, having lasted 18 days and 8 hours, a Guinness World Record that still stands today.