During the last full weekend in June in the ultra-running world, there’s only one place to be: the Western States 100.

Arguably the most prestigious ultra-running race on the planet, the Western States 100 starts in Olympic Valley and ends in Auburn. It snakes through the North Sierra Nevada along the infamous Western States trail for 100 miles, following a route carved into the mountains by gold and silver miners of the 1850s.

As if the sheer distance wasn’t enough, the terrain is particularly harsh. The trail demands that participants climb 2,550 vertical feet in the first 4.50 miles. If a racer wants to bail midway through, they might be out of luck — much of the course is accessible only by foot, horse or helicopter — and helicopter evacuations aren’t cheap. Most of the time, the only way out is through.

While it might sound like the worst possible way to spend the first weekend of summer,  the Western States 100 has taken place since the 1950s — with one key difference. Until the early 1970s, the competition was on horseback.

In 1972, a 20-something long-haired hippy from California named Gordy Ainsleigh was slated to compete in the Western States horse ride. Leading up to the race, however, his horse’s health declined substantially. Rather than drop out of the event altogether, Ainsleigh laced up his sneakers and ran the entire course on foot. At the aid stations, his vitals were checked by the on-call veterinarians. Miraculously, Ainsleigh finished his run within the twenty-four hour cutoff for all horses.

Ainsleigh’s feat called all of the trail running lunatics out of the woodworks and onto the course. By 1977, the starting line was too crowded with trail runners for any horse to join the fray.

Ainsleigh is now in his 70s — but while he still trail runs, rock climbs, rides a mountain bike and works as a chiropractor, it’s unlikely that he will race the Western States 100 again. But his bizarre choice nearly 50 years ago altered the trajectory of the entire ultra-running sport and gave rise to one of the most iconic ultra-running events on the planet.

Entrants from all over the world are flooding into Placer County for 2022’s Western States 100 hellscape. This summer is slated to be one of the hottest on record, but in the Sierras, racers will need to prepare for every extreme. Daytime temperatures of 110 degrees Fahrenheit could drop to 20 degrees Fahrenheit by nightfall.

Because of the obvious risks involved, the prestige of the race is upheld by a rigorous admission standard. Applicants must finish a qualifying race before being entered into a lottery. If selected, they’ll pay $410 — and an online processing fee, of course — for their race admission (Yes, people pay to do this).

Each year, the top 10 finishers earn a reserved spot for the next year. Elite runners can also qualify through the HOKA Golden Ticket Races — a series of brutal ultras that earn the top two finishers for both men and women a ticket to the Western States 100.

The highly selective entrance process gives some insight into which racer might cross the tape first in Auburn.

Tyler Green, 38, crossed the tape second last year. This year, he will be vying for his third Western States 100 finish and another spot on the podium against a talented field. Several top-10 qualifiers and Golden Ticket recipients might have what it takes to beat out Green, including Drew Holmen of Colorado, Cody Lind of Idaho and Arlen Glick of Ohio.

Last year’s second-place female, Ruth Croft will be out for blood after narrowly missing the win last year. The 33-year-old from New Zealand trains all over the world, but has spent the last several weeks logging miles in the Sierra.

Croft’s biggest competition might be the Golden Ticket qualifiers. Runners like Camille Herron, 40, who earned her Western States spot by winning a 100-meter race in Arizona, is clearly no stranger to the heat. Known for downing tacos and beer while speeding through ultras, Herron might just have what it takes to win.

Lucy Bartholomew, 26, has arrived in California from Australia to take on the Western States 100 for the 3rd time. Despite being several years younger than many of her competitors, Bartholomew comes with a high level of familiarity with the course — this knowledge is invaluable, as the trickiest parts of the race are often covered in the dark. Based on recent interviews, Bartholomew feels more mentally prepared than ever.

Flying all the way from France, Camille Bruyas, 30, earned her Golden Ticket after a second place finish at an ultra in Europe, the UTMB 171K. Her chances of winning at UTMB were slim from the start — she toed the line against household name Courtney Dauwalter, arguably the best ultra runner in history.

Dauwalter has her eyes set on the Hardrock 100 in July, so she will be sitting out of the Western States 100. With Dauwalter absent from the starting line, it could be anyone’s game.

For Berkeleyans looking for a hometown hero to support, 44-year-old Samuel Nickelsen will be toeing the line on Saturday as the sole runner representing Berkeley. Nickelsen will be attempting his first Western States 100 finish — hopefully, Berkeley’s hills have prepared him for one of the gnarliest ultra marathons on the planet.

While this weekend’s competition will be fierce, the best things to come from ultras are not first place finished, but good stories. Stories of pain, defeat, triumph, glory, vivid hallucinations, missed turns and bathroom horror stories quickly turn to legend within the ultra-running community. After all, the Western States 100 race was founded on one really good story — the story of a man who dared to race against horses.