Have you ever considered running a distance equivalent to almost four marathons in a row? We’re going to go out on a whim and say no.

Competitors in the Grand Raid de la Reunion La Diagonale Des Fous race are currently doing just that. This year marks the mountain ultramarathon’s 20th anniversary, and it all unfolds on the French-run Reunion Island – a slice of Africa in the Indian Ocean between Madagascar and Mauritius.

La Diagonale Des Fous, meaning Madmen’s Diagonal, starts at St. Philippe, in the south of the island. It involves climbing up and down five peaks that soar some 2,000 meters before finishing at Saint Denis, the island’s administrative capital set at its northernmost point. En route, racers skirt volcanic slopes, wind through ravines and slog through ankle-deep forest mud. Only the toughest, fittest runners finish the grueling challenge that stretches over 99 miles. Those in the mood for something a little less insane can consider the two shorter alternative Reunion marathons: the 57.8 mile Bourbon Trail (October 20-21) and the 37.9 mile Mascareignes Raid (October 20).

When it comes to Reunion Island’s volcanic landscape, think rugged mountains crisscrossed by torrential rivers and rich with exotic wildlife.

Maybe 99 miles in paradise isn’t so bad.

Cover Photo – Wikimedia Commons