Orinduik Falls are on the Ireng River, about a 20 minute Cessna ride southwest of Kaieteur, forming the border of Brazil. These falls are located on the sun-scorched grassy savannas of the Pakaraima Mountain foothills, in stark distinction to the dense rain forest surrounding Kaieteur Falls. The difference is stunning. The onset of the savanna is known as the Rupununi, occupying the lower 1/3 of Guyana. All that is there are a few sparse houses and a dirt landing strip.
I would challenge any seasoned traveler to find a better and more dramatic "swimming hole" in the world. The breathless scenery is only mildly tempered by the nasty kaboura flies (Pauline Melville comments on them in her Ventriloquist's Tale, p. 98).