Tommy Caldwell and Alex Honnold have completed a huge linkup of peaks in Rocky Mountain National Park, Colorado. Taking roughly a day and a half, the pair linked climbs from Mount Meeker to Mount Notchtop, naming the challenge the 'Continental Divide Ultimate Linkup' – or CDUL (pronounced cuddle).

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I guess my wish for a character-building experience paid off. From a runner's perspective we made some rookie mistakes. We missed our pre night support drop off and therefore ended up climbing through the night in our short shorts and howling winds at 13000 feet, phone jammed under my hat as a flashlight. Calorie deprived until our Hero @adam_stack rescued us with food and headlamps. By mid-morning I was throwing up. @alexhonnold of course was steady and high spirited as always. We completed what I'm calling the Continental Divide Ultimate Link, (CDUL, pronounced cuddle for how we warmed up in the middle of the night) after 36.5 hours. 17 mountains, 11 classic climbing routes, 35 miles and about 20k of vertical gain. Thanks, Adam, for helping dream this idea up, and for the incredible support, and the fun photos. Thanks, @maurybirdwell , for the resupply and uplifting conversation at the beginning and end. Thanks to @beccajcaldwell and @sannimccandless for skinny dipping in the lake below as we descended the last mountain therefore motivating us to quicken our pace. And of course Alex always deserves a hearty thanks for dragging this aging dad on some awesome adventures.

A post shared by Tommy Caldwell (@tommycaldwell) on Jul 21, 2020 at 4:12pm PDT

The ground covered by Caldwell and Honnold was impressive – they were moving for around 36.5 hours and covered 35 miles, 20k feet of vertical ground, 65 pitches and 11 routes. They were supported by Adam Stack and Maury Birdwell, who provided food, essential gear and other resupplies.

By Caldwell's own admission, they made some 'rookie errors' from a runner's perspective, missing their pre-night support drop off which left them climbing in short shorts and without food at 13,000ft in howling winds. Their headlights ran out and he resorted to jamming his phone under his hat.

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@tommycaldwell and I just climbed what he's calling the Continental Divide Ultimate Linkup (CDUL, pronounced cuddle, for how you stay warm during the night...). We climbed 11 classic climbing routes and summitted something like 17 named peaks across RMNP. We traveled from Meeker to Notchtop, which required basically 36 hours of constant movement with roughly 20k ft of vertical and 35mi of scrambling between the peaks. Though the stats don't mean much because the terrain is so rugged that it's hard to characterize it as "hiking". Huge thanks to @maurybirdwell and @adam_stack for supporting us during the journey with key resupplies. And thanks Adam for this cool pic of us on the summit of Sharkstooth at sunrise. Big day out!!

A post shared by Alex Honnold (@alexhonnold) on Jul 20, 2020 at 9:57am PDT

According to Stack, who 'rescued' them with food new head torches, the quote of the night from Alex was 'soloing by iPhone is not that sweet.' By mid-morning, the CDUL was taking its toll on Caldwell who began throwing up.

The pair had been preparing for the CDUL for a couple of weeks. On June 10th, they had scoped out half of the challenge - from Mount Meeker to Mount Alice – which Honnold described as a 'lovely day out' with his 'favourite mountain guide.'

Honnold provided a full list of the routes which they mainly simul-climbed:

• Flying Buttress on Meeker (5.9)
• Casual Route on Longs Peak (10-)
• Pagoda
• The Barb on Spearhead (5.10)
• Birds of Fire on Chiefshead (5.11-)
• Central Ramp on Mount Alice (5.8)
• Arrowplane on Arrowhead (5.11-?)
• McHenry
• Powell
• Taylor
• The Petit (5.8)
• SW Corner on Spearhead (5.10)
• Sharkstooth (5.6)
• Otis
• Culp-Bossier (5.8+) on Hallet Peak
• Flattop
• Ptarmigan
• 'The cool crack' on Notchtop (5.9)

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99.9% of people would have given up when they did not have a headlamp or food for part of the night. The quote of the night "Soloing by iPhone is not that sweet." Alex Proud of @alexhonnold and @tommycaldwell for an epic effort and setting a new bar for what is possible when you combine ultra running and climbing. Around 35 miles, 65 pitches, for a total of 20k in vert. I think it will be a while until the CDUL gets repeated. As a parting thought, I've always wondered if Tommy was human. I had to include the 2nd photo as proof he is. Love you buddy, way to push through the pain.

A post shared by Adam Stack (@adam_stack) on Jul 20, 2020 at 3:25pm PDT

This wasn't the first time the two climbers have teamed up for a massive enchainment. In February 2014, the pair made the first ascent of the Fitzroy Traverse in Patagonia, Argentina. The 5km ridge line covers huge granite spires, including Cerro Fitzroy at 3405m. With thousands of feet of abseils, loose rock, difficult route finding, heavy packs and despite only bringing enough food for 3 ½ days, it took them 5 days in total. The ascent was featured in the film 'A Line Across the Sky' by Reel Rock.