Meet the woman who ran 20 marathons in 30 days along the Seine An Australian environmental activist has become the first person to run the entire length of the Seine River, a total of 848km from its source to the sea, in 30 days. Mina Guli set off on this epic journey last month to draw attention to efforts being made to clean up the Seine, and the need for all cities to restore rivers. The 53-year-old completed her Seine River Run challenge earlier in July, crossing the finishing line in the port city of Le Havre.