BOSTON (CBS) – Thousands of cyclists have hit the road for the annual Pan-Mass Challenge, which is the largest athletic fundraiser in the country.

More than 6,300 riders took off from various locations on Saturday morning to begin their ride in hopes of raising $46 million for cancer research.

The longest route is a 192-mile journey from Sturbridge to Provincetown over two days.

There are shorter one-day rides on both Saturday and Sunday as well.

More than 4,000 volunteers help the event run smoothly.

Since Billy Starr founded the Pan-Mass Challenge in 1980, more than $500 million has been contributed to cancer research.

“It’s a great group of people. The logistics surrounding this event are enormous,” Starr told WBZ-TV on Saturday from the starting line.

The Pan-Mass Challenge generates more than 50 percent of the Jimmy Fund’s annual revenue, and it is Dana-Farber’s largest fundraiser.

Riders hope to surpass the event’s 2015 total of $45 million raised.

“Together we should make $46 million,” said Starr.