This is possibly the easiest to find of the 'hidden' locations in Meadow. It's not actually very hidden at all and can be seen very easily from anywhere in the snow biome (south west of the centre tree). You need to head to the giant monolith in the snow biome. A path runs up the rock the monolith is sat on and to trigger the achievement you just need to walk up the path to the base of the monolith. If you're lucky there will also be lumps of essence of various colours scattered around the monolith.