Originally Posted by Tai_MT
It's Uphill Both Ways
Complete the game without setting foot in a vehicle (Excludes Supply Drop and vehicle-based quests).
Done if we're not counting hang gliders that are NECESSARY for relic collection to be flown.
If you're talking about some of the relics on Islands that don't seem to have a way up you can actually climb those hillsides using a modified version of the ElderScrolls/Fallout mountain "hack" jump. Basically you just run at various angles spamming the jump button and you eventually make it up something you weren't supposed to be able to climb.