MILWAUKEE (CBS 58) -- Downtown Milwaukee is preparing for the USA Triathlon National Championships. The first events begin Friday, Aug. 4.

Parking restrictions are already in place, and Lincoln Memorial Drive will close for the extended weekend.

Thousands of athletes are in town from across the country and around the world.

Marissa Werner, the Director of Sports Milwaukee, said, "It's very interesting, just walking the grounds you will cross paths with people from Ecuador, or Canada, or California."

And you can expect to see many more flags throughout downtown Milwaukee in the coming days.

Thousands of people will flock to the lakefront for three days of triathlons.

USA Triathlon is hosting age group national championships & junior and youth championships.

At the same time, the Professional Triathlete Organisation is holding a two-day event for the top-ranked pros in the world, many of them Olympians. The race will be broadcasted in the United States and Europe.

On Thursday, many got familiar with the course ahead of the competition days.

Werner said, "It's just really a great way and a great event to bring all these different people to experience Milwaukee and everything we have to offer."

VISIT Milwaukee estimates more than 7,000 athletes will take part. They and the fans could bring in an estimated $9 million in economic impact.

"They're coming to a competitive race on a challenging course, but at the same time, those athletes travel with family", said Brian D'Amico, the Director of Athletic Events for USA Triathlon. "On average, our athletes with the US Triathlon side travel with an additional 2.2. persons."

In addition to racers, the event brings out about 15,000 spectators.

But local athletes are also finding ways to participate, like Milwaukeean Filip Warminski, who said, "I just went online and signed up last week, and here I am."

While some locals will be on the course, others will have to avoid it.

Lincoln Memorial Drive will shut down Friday through Sunday. Parking restrictions are already in place.

Werner said, "We understand event fatigue for residents and partners, and we do the best that we can to work around that."

After hosting the triathlon for the past several years, this will be the last time Milwaukee hosts for a while.

And while there is big prize money at stake for the pros, others are excited just to compete.

Warminski said, "I really don't compete against anybody, just myself. I just want to finish and be happy with myself for finishing it."

The first competitions begin Friday at 8 a.m. and will continue all day, every day through Sunday.

Click here to find out race schedules, and more information about this event.