Over 950 people from around the world gathered Sunday at Lotte World Tower to do one thing: climb up 123 floors -- or 2,917 stairs to be exact.
Gripping banisters and taking the stairs two at a time, the climbers aimed to run up the top of South Korea's tallest skyscraper located in Songpa-gu, eastern Seoul, as part of an international race hosted by the Vertical World Circuit.
"I've always enjoyed pushing myself past the limit," said Park Soon-eek as he was warming up in the Arena Square near the start line.
The 60-year-old participant regularly takes the stairs to stay fit and avoids using an escalator in an office building as often as possible for daily exercise.
"It's absolutely a free way to improve cardiovascular health and muscles without the need for any training or skill, especially those in sedentary office life."
Under the slogan "Beautiful Challenge for A Heartwarming World," the vertical running competition started at around 9 a.m., with groups of professional and amateur stair climbers.
To get a feel of the race, this correspondent from The Korea Herald took part in the event.
For a slightly overweight 29-year-old reporter who cycles for leisure, the task that lay ahead was nothing if not daunting as I headed to the start line and ran into Lotte World Tower, where a mercilessly long stretch of stairs awaited a novice challenger like myself.
I nervously stepped into the race, but within minutes my lungs started screaming in agony, gasping for air.
Going round and round, I caught up with slower runners upstairs, who later darted off again as I was getting noticeably slower with my quads burning.
On the stairway, cheery marshals and first aiders occasionally shouted to climbers, saying "You can make it," and "Let's go, let's go."
Trying not to trip while attempting to shoot a video along the way, I took notice of a sign on the wall to figure out how far up I was and how many floors I had to climb to finish this self-imposed torture.
After several holdups due to a sore back, I finally sprinted to the finish on the last 10 floors and reached the top in 39 minutes and 1 second.
Half a kilometer above the ground, the world's fifth-tallest landmark offered visitors a stunning view of the Han River and Seoul's wide cityscape through the window. I felt a sense of pride and relief.
A non-competitive charity race was also held on the same day and its participants included police officers, firefighters and local government officials, as part of fund-raising for young athletes.
"All entry fees will go to Child Fund Korea to support young talented athletes from broken families," Lotte Corp. CEO Park Hyun said.
Professional runners raced first in groups of 10, sprinting up to the observation deck located at the top floor of the building.
Mark Bourne from Australia came in first, finishing the race in 16 minutes and 44 seconds.
Suzy Walsham, also from Australia, clocked 18 minutes and 47.23 seconds, finishing first among professional female athletes.
The top three in the male and female categories received a total of 12 million won (S$14,811) in prize money and trophies.
Following the elite group, amateur athletes, like myself, started climbing.
The top amateur runners also received 1.23 million won worth of Lotte gift certificates, a one-night voucher at Lotte Tower's six-star hotel, Signiel, and 200,000 won worth of Lotte Duty Free's prepaid card.
Not everyone joins the race to compete. There are people who "love to see the sense of accomplishment" that comes after hard work.
"Stair-climbing challenges me and always gives different intensities depending on speed and the number of stories," said a 20-something female participant on the observation deck, enjoying the view.
"But at the end of the day, you end up having a great looking butt and thighs. It's a great way to achieve results quickly.
One handicapped runner said he would willingly donate 5 million won to the child fund charity group, according to Lotte.
"We have so many inspirational people around us who change the world with talents and skills. And I'd also like to lead my life, filled with dreams and hope," he told the company.