Gruta do Lago Azul, located in Bonito, Brazil, is a stunning cave with a crystal-clear blue lake at the bottom. Visitors take a short walk down to the lake and back up, admiring the beauty of the natural surroundings. Although the cave itself may not be super fancy, the mesmerizing blue water makes it a must-see spot for anyone exploring the area. Just make sure to book in advance because this popular attraction tends to fill up fast!