HOUSTON - Marathon weekend is here and on Friday, a sea of running enthusiasts filled the George R. Brown Convention Center for the Memorial Hermann IRONMAN Sports Medicine Institute EXPO.

Among them was marathon pacer Alan Tillotson.

“I’m very excited, weather is gonna be perfect, I love this race,” he said.

The expo is a one-stop shop to all things marathon related. From information about the races, to making sure racers have everything they need to run.

Just outside the convention center, crews worked to put the finishing touches on the finish line ahead of the big race Sunday. The crowds inside provided a glimpse at just how big the event is.

“At 7 a.m., the Chevron Houston Marathon and the Aramco Houston Half Marathon run will feature 27,000 runners. We’ll have 250,000 spectators, hopefully bundled up ready to cheer on the amazing elite field we will have,” said Wade Morehead, the executive director of the Houston Marathon committee.

Related: Street closures for 2018 Chevron Houston Marathon

The route is pretty similar to last year’s but race organizers say many may notice it’s different than years’ past.

“We’re going to be running through neighborhoods from some of the areas that were flooded,” Morehead said.

For Tillotson, seeing those neighborhood will hit close to home.

“A lot of my friends, including me, lost everything in Harvey,” Tillotson said.

This year’s shirts reflect the city’s motto following the storm - 'Houston Strong'. Tillotson says it’s a great bit of motivation for the 26-mile trek.

“It nice way to see put Harvey behind us put it in our rearview mirror,” he said.