Originally Posted by bigbear2face
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.
Pretty sure Relic 107 (Heron) near Gaztwon (left most town on Island 2) is ONLY obtainable with the Hand-glider. No other way possible to get that one.