boulder canada destination direction hike landscape mountain natural nature north america rock trail travel Trek vignette walk America aquamarine blue clean clear cold fast flow pool pure river transparent water conifer forest tree boulders cliffs colours gorge grand canyon layers national park ravine rocks rugged sandstone stone stony trees usa aftermath catastrophe dead death destroyed destruction fire lakeside recovering recovery Remains beach coastline Cornish cornwall England english Great Britain ocean sand sandy sea sheltered shore spring tide waves wild caves cliff coast danger green Pembrokeshire view wales welsh cyprus hazard horizon mediterranean reef shoreline current fierce norway norwegian rapid slope strong lake moraine ripples Rockies rocky sunlight