What to know about the 49th Detroit Free Press Marathon happening Sunday

The top-ranked marathon in the country, according to USA Today, is back this weekend.

The Detroit Free Press Marathon takes place Sunday, with several other events leading up to the big race.

The marathon brings in thousands of runners from all over the world, and once they hit that start line, you might not realize how many of them are giving back once they hit the finish line.

"It's a lot colder in the morning for folks to warm up, and a lot of them will wear extra layers of clothing that they will discard right at the start of the race or shortly thereafter," said Detroit Free Press Marathon race director Aaron Velthoven.

These runners don't expect to get those warm-ups back either. Instead, those extra layers get a second wind.

"We're able to give those items of clothing to local area shelters, which is a tremendous thing for us to do. We've been doing it for many years. Sustainability is so important for us," Velthoven said.

With roughly 34,000 participants and even more in attendance cheering them on, the Detroit Police Department says they'll have officers out to ensure a safe event.

Those traveling downtown are encouraged to arrive early on Sunday due to road closures along the route.

Fort Street will be closed from Grand Avenue East into downtown. Lafayette will have closures from Iroquois to downtown. Woodward Southbound will be closed starting at Adelaide Street near Little Caesars Arena. The Lodge will also be closed for those heading downtown after the Howard Street exit.