A 70-year old grandfather has successfully rowed a boat unassisted across the entire Atlantic Ocean-and he did it for others.

As part of a challenge to raise money for research on Alzheimer's treatments, Frank Rothwell dedicated the extreme feat to his brother-in-law Roger, who succumbed to the disease during Frank's crossing.

A little more than £1 million ($1.39 million) was raised by almost 10,000 different donors, including a doubling of the first £500,000 ($695,000) from Iceland Foods Charitable Foundation.

Requiring 18 months of hard training, the entire row took eight grueling weeks for Rothwell to travel from La Gomera in the Canary Islands on December 12 to the finish line 3,000 miles away in Antigua on February 6.

"I like a challenge!" explains Frank on his fundraising site. "In 2017, I spent five weeks on a deserted island for the Channel 4 program, The Island with Bear Grylls. Before that I was only the 10th person to ever circumnavigate North and South America."

In a statement, Hilary Evans, chief executive of Alzheimer's Research UK, said: "We're honored to have such amazing support from Frank. His courage and determination helped him to complete his epic challenge and raise £1 million for dementia research."

"This incredible amount will be a huge benefit to the groundbreaking research we carry out here at Alzheimer's Research UK, as we continue our mission to bring about life-changing treatments for people affected by dementia."

Crossing the finish line was a euphoric and emotional moment for Rothwell. He said: "I am on cloud nine! I set out in December wishing to raise £1 million for Alzheimer's Research UK but I never thought I'd actually achieve it. The challenge was incredibly tough at times, with rough seas, huge waves, and missing my wife, Judith. But as exhausting as it was, it was all totally worth it."

"Having received hundreds of messages from people who, like me, have witnessed the heartbreak of dementia, I am proud to have raised such an incredible amount in honor of Roger, and everyone else who has experienced the devastation it causes."

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