Nicholas Tremaine is on a gruelling year-long journey, cycling more than 40,000 kilometres around Australia to raise funds and awareness of dementia.
Pedalling unsupported a distance equivalent to the circumference of Earth is putting the 34-year-old's endurance, resilience and willpower to the test.
"It's like a rollercoaster," he says.
" There've been some really good highs, but then there're often some low lows. "
Even after a broken bicycle frame in the outback, extreme heat, deep emotions and aches, no-one can deter his sheer determination to push on to the finish.
It is a cause close to his heart, inspired by his mother, Marilyn, who lives with dementia.
"If she was able to, I know she would be at the finish line to see me finish," he says.
"That's what pushes me through, no