Cupid's Undie Run raises money for Children's Tumor Foundation

Hundreds of people will take to the streets of San Francisco for Cupid's Undie Run on Saturday.

It is the largest undie run in the world, with 38 cities participating annually.

Last year, the run raised $3.5 million for the Children's Tumor Foundation.

The Valentine's themed fun run is 1 mile with a  large celebration after.