They come around a gentle bend in the river and are confronted by a waterfall some twenty meters high. At the base of the falls there’s a still and relatively shallow pool, filling the bottom of a broad melon-shaped cavity formed by the concave, overhanging banks. The vertical sun beams straight down on the cloud of white foam at the base of the falls, which radiates the light back at blinding power, forming a sort of natural light fixture that illuminates the whole inside of the cavity. The stone walls, sweating and dripping and running with groundwater, glisten in its light. The undersides of the ferns and big-leaved plants—epiphytes—sprouting from invisible footholds in the walls flicker and dapple in the weirdly bluish foam-glow.