The 3,100-mile Olympic torch relay is underway. Here's what to know about the symbolic tradition.

The Olympic flame has been lit in Olympia, Greece, kicking off the torch relay for the 2024 Paris Olympics. Ahead of each Summer Olympics, the torch is lit in the ancient site where the games were founded, connecting the event back to its roots.

The torch is carried to the host city by runners and other modes of transportation. This year, the torch will be carried to Athens and then taken on a three-masted sailboat across the Mediterranean Sea to Marseille, France. It will travel around...