SAN FRANCISCO - MAY 17: (EDITORS NOTE: THIS IMAGE CONTAINS PARTIAL NUDITY) Nude participants take part in the ING Bay to Breakers race May 17, 2009 in San Francisco, California. Now in its 98th year, the ING Bay to Breakers 12K is one of the world's largest and oldest footraces, featuring world-class athletes in addition to costumed runners. (Photo by Ezra Shaw/Getty Images) Nude participants take part in the Bay to Breakers race May 17, 2009 in San Francisco. (Photo by Ezra Shaw/Getty Images)

SAN FRANCISCO (KCBS)— San Francisco Mayor Ed Lee revved up the troops at City Hall on Tuesday for this weekend’s Bay To Breakers foot race, but city officials want to make it clear that this event is about having fun while being safe.

So far 40,000 runners have registered for the big event Sunday, May 18th, which is boasted as the oldest consecutively run annual footrace in the world.

“This iconic race is celebrating its 103-year history,” Lee proclaimed.

The 12K race stretches from the Embarcadero, west out onto the Great Highway.