The Meeting of Waters is an astonishing natural phenomenon where the dark waters of the Rio Negro meet the sandy-colored waters of the Solimoes River to form the Amazon River. The two rivers run side by side for approximately 6 kilometers without mixing due to differences in temperature, density, and speed. The Rio Negro is warmer (28C) and slower, while the Solimoes is cooler (22C) and faster. This unique spectacle is one of the most impressive wonders of the Amazon and can only be fully appreciated from a boat tour.