The Merrell Down & Dirty Obstacle Race swept through Los Angeles last month and is about to land in Miami, before tearing into nine other US cities before the end of the year.

This Sunday’s (May 18) Miami race is the usual grueling three or six-mile thriller. Fast and flat, it takes in the perimeter of Zoo Miami and the surrounding forests, snaking through moats and thick woods.

Obstacle highlights that brave athletes can look forward to tackling include:

Slippery Mountain

A highlight of the Miami event, The Slippery Mountain was first introduced by MESP way back in 1996, and has been used in thousands of different races. The eight-foot structure is produced with 70 pieces of wood and over 200 bolts (meaning it’s worked its way through 6,790 pieces of wood and 19,400 bolts and screws in total). Gallons of water are added, making it the toughest, slipperiest climb on the course, which demands those who face it to pull themselves over the top on their bellies with the help of volunteers.

Heavy Hoist

Racers will run up to the new Heavy Hoist to pull a rope attached to a cement block (80lb for men, 40lb for women) all the way to the top of a tower. To create a greater challenge, racers will stand five feet back from the obstacle to pull the rope, forcing each participant to use all of their body weight.

Jim’s Jungle Jim

On this new obstacle, participants will climb 10 feet using small footholds on a steel pipe, descending down a cargo net once they reach the top.

Cargo Climb

Athletes will approach a 12-foot high A-Frame structure with a cargo net attached, and climb over using the netting for footholds. It should take no longer than 45 seconds for each entrant.

Monster Climb

A huge hit in 2013, this hardcore challenge will see competitors maneuvering over and down a series of cargo climbs – a true test of nerves, strength and speed.

After Miami, the Down & Dirty moves on to Chicago on June 1st, followed by Dallas, Hartford, Washington D.C., Philadelphia, Detroit, New York and Atlanta, before hitting Sacramento in November.