* Organisers want to favour long-range attacks * It's quite a challenge, says defending champion Froome * Race to go through all French mountains but fewer summit finishes (Adds quotes, details) By Julien Pretot PARIS, Oct 18 (Reuters) - Organisers have unveiled an unconventional route for the 2017 Tour de France featuring many early climbs in a bid to limit the opportunities for strong teams to dominate stages and reward aggressive riders looking to shake up the sport's greatest spectacle. Race director Christian Prudhomme peppered the 2017 course with steep climbs, five of them making their first appearance on the Tour and many early in stages, which will start from Duesseldorf on July 1 and go through five countries before ending in Paris on July 23. More...