This weekend, L.A. will be packed with events attracting huge crowds that are, in turn, also attracting a lot of attention from area law enforcement.
"We're a little more focused right now because there has been a recent attack," said L.A. County Sheriff's Lt. John Sullivan.
Sullivan says because of the Boston bombings, roughly 50 law enforcement agencies will be busy monitoring this weekend's events. And they will have their hands full.
In Long Beach, some 170,000 spectators are expected to attend the three-day-long Grand Prix of Long Beach.
In Los Angeles, Sunday's sixth annual CicLAvia will pack 15 miles of streets from downtown to Venice Beach with tens of thousands of bicyclists.
In Pasadena, the Los Angeles Walk Now for Autism Speaks is expected to draw more than 40,000 people to the Rose Bowl on Saturday.
At USC, the two-day-long L.A. Times Festival of Books -- the largest in the country -- will bring in thousands more.
And with all those people at all those events, the Sheriff's Department says it too will be bringing in more people to keep the peace.
"We've opened our Emergency Operations Center, we're monitoring the entire system, where deputies are, where trains are, where the crowds are gathered," said Sullivan.
Over at the Rose Bowl, Pasadena Police are also gearing up, taking extra precautions in light of the Boston attack.
"We have other law enforcement partners who will be here, some of them will be visible in uniform, others will not be readily noticeable," said Pasadena Police Lt. Tracey Ibarra.
With so many people heading to events this weekend, security is also being boosted at Union Station, with explosives-sniffing dogs and high visibility officers. But for some riders, it's still not enough to ease their fears.
"Someone might sabotage a train where a lot of people are gathered, so I'm reluctant," said train rider Madeline Klose.
But others say they aren't going to let the bombings ruin all the big crowd events available to them.
"If I got the money, I still will go. No problem at all," said Buena Park resident Maurice Kelly.