An American cancer survivor has achieved the "extraordinary" feat of becoming the first person to swim across the English Channel four times non-stop.
Sarah Thomas, 37, said she felt "really tired" and "stunned" after completing the epic challenge in just over 54 hours.
The swimmer from Colorado was cheered to shore at Dover and handed champagne and chocolates as her remarkable swim ended at about 6.30am on Tuesday.
Her achievement, described by supporters as "mind-blowing", comes just a year after Ms Thomas completed treatment for breast cancer.
Writing ahead of her challenge, she dedicated the swim to "to all the survivors out there".
Afterwards, Ms Thomas told BBC Breakfast she felt "stunned" and "numb".
The hoarse-sounding swimmer said: "I'm really tired and I'm losing my voice from all the saltwater."
Asked what the worst part of her challenge was, she said: "Probably dealing with the saltwater over four days, or two days, it really hurts your throat, your mouth and your tongue."
She praised her support team for "helping me stay strong", adding that she was "very prepared" for the weather, currents and cold water.
Ms Thomas said she was kept fuelled by electrolyte and caffeine-filled drinks as she navigated past "a lot of jellyfish" during her swim.
She admitted to feeling "pretty out of it" and was hoping to "sleep the rest of the day".
The swimmer added: "I feel just mostly stunned right now, I just can't believe that we did it."
Elaine Howley, a member of Ms Thomas's support team, said the swimmer had returned to her accommodation near Folkestone with her family to sleep and recuperate.
Describing her friend's achievement, she said: "It's unfathomable, it's super human, it's just extraordinary.
"I'm not sure there are enough superlatives out there to explain what this meant on many different levels."
Ms Howley, from Boston, who herself made a single swim crossing of the Channel in 2009, said she had occasionally jumped in the water to pass Ms Thomas food and drink and accompany her on lap turns.
She said the total official crossing distance was 84 miles, but Ms Thomas likely ended up swimming further due to currents and tides, with the latter shifting unexpectedly in the final stages of the challenge.
"It's no joke," she said of Ms Thomas's challenge. "It's cold, it's a long way, the tides and the currents are really tricky."
Ms Howley said she first met Ms Thomas in 2013 after she completed a 50-mile swim.
Preparations for the Channel swim began two years ago but were put at risk due to Ms Thomas's cancer treatment.
Ms Howley said: "Knowing the year that she's been through, with the cancer, it's really important, it's huge for her.
"But she's also pushed out the boundaries of the sport of marathon swimming."
She added: "The world of marathon swimming is super proud of her, we're all just thrilled and pleased that she was able to be successful with us."
In a video live-streamed on Facebook, a crowd of people could be seen cheering on Ms Thomas as she made her final arrival to shore at Dover.
In the video, Ms Thomas admitted to feeling "a little sick" but said she had been encouraged to "keep going" by her husband and her team.
Ahead of the start of her epic challenge, Ms Thomas wrote that she was "scared" and admitted she was "going to need some luck".
In a Facebook post made on Saturday, she dedicated the swim "to all the survivors out there", adding: "This is for those of us who have prayed for our lives, who have wondered with despair about what comes next, and have battled through pain and fear to overcome.
"This is for those of you just starting your cancer journey and those of you who are thriving with cancer kicked firmly into the past, and for everyone in between."
Photographer Jon Washer, from Boston, who is producing a documentary on Ms Thomas's challenge, also lauded her achievement.
He said: "This whole experience has been devastatingly hard, but seeing Sarah finish was one of the most emotionally rewarding moments of my life, and I've only known her for about six months.
"My job was to cover her landings, all four of them, from the shores, so I got more than familiar with the Channel Tunnel the last few days, and that felt impossible.
"But knowing what Sarah was just able to do. It is just mind-blowing."
The Channel Swimming & Piloting Federation congratulated Ms Thomas on "completing a 4-way historic crossing of the English Channel", describing her on Twitter as "an absolute legend".