Hundreds of world-class cyclists have arrived in Chattanooga for the most prestigious cycling race in the country. The Scenic City is hosting the USA Cycling National Championships for the second year. Some of the top athletes say our landscape is making it one of the most challenging courses they've ever raced.

Time trials start Saturday morning out at Enterprise South. The road race is on Monday. The 16 and half mile circuit stretches from the North Shore to Lookout Mountain. The athletes are getting in last-minute training all for a chance to represent the US in the prestigious "stars and stripes" jersey. Local leaders say it's also a chance in the spotlight for the Scenic City.

Cyclists spent Friday gearing up out by Volkswagon at Enterprise South as setup continues. It's the course for the time trials Saturday and Sunday, aka "the race of truth." They start in intervals, so it's just them, the road and the clock. Then, Monday is the road race. 25,000 people are expected to line the streets.

"The eyes of the world are on Chattanooga," Chattanooga Mayor Andy Berke said.

Local leaders say this world-class event helps brand Chattanooga as a mecca for athletes and outdoor enthusiasts. Last year's men's road race champion Freddie Rodriguez says riding the Scenic City is no joke.

"It's already one of the hardest courses I've ever raced when it comes to a one day race," Defending Men's Road Race National Champion Freddie Rodriguez said.

An added challenge this year is the 20-percent grade on North Shore's Kent Street.

"The riders as they do those long laps and those short laps will have to go up that 20-percent grade numerous times throughout the day so we think that's going to break the feel up just a little bit," USA Cycling Chief Marketing Officer Rob Borland said.

Crews laid down fresh asphalt this week along Frazier Avenue. That's a good vantage point for spectators, not only for the hill, but also the hairpin turn from Forest to Frazier. It's something the para-cyclists will also take on.  

"Anything with hills and turns is right up my alley and just because we're disabled, doesn't mean we don't want the challenges of a course. So it's an honor to be able to race on the same course as the pros will be racing on, but it's going to be tough," four-time Para-cycling World Champion Jamie Whitmore said.

23-year-old Taylor Phinney, being called cycling's "next big thing," has his eyes on being the first national champion to win both the time trial and road race. He came a day earlier to peak at the course and get a feel for the city.

"I really like it here so far. It's got this southern hipster feel, which I enjoy," Phinney said.

Organizers are trying to make the event more viewer-friendly this year. They're airing live streams on big screens sprinkled throughout the course.

There will be various road closures the next three days so you know where to look for, or avoid, the race. We have all those posted here.