For four years Isabelle had wanted to concretely trace the "M" formed by the sites of the Virgin Mary’s apparitions throughout the 19th century in France. When she returned from WYD in Cracow, she submitted her idea to Marie and Xavier, who immediately said “yes.” All three embarked on this adventure. "We will go on pilgrimage in the footsteps of the Virgin Mary. We want to put our country back under her protection. We will pray … and push pedals for the conversion of our country and that of our souls."
On July 14, 2017, 12 young people set out on this pilgrimage. They finished it on August 15th, feast of the Assumption and a national holiday in France. Their bike trip traced the great "M" of Mary formed by the Marian apparitions of the 19th century on France: from Lourdes (July 14th), they traveled to Pontmain (July 25th), then Pellevoisin (July 28th-29th), then L’Ile Bouchard, followed by Paris, at the Miraculous Medal, rue du Bac (August 1st, with a night of adoration at the Sacred Heart Basilica of Montmartre that same day). On August 14th, they arrived at la Salette with a stop on the way at Paray-le-Monial, where Jesus revealed his "Heart burning with love for humanity."
Source: Isabelle, Marie and Xavier
You can see the M of the hike on this link