Negro River

The Rio Negro is the largest left tributary of the Amazon River, accounting for 14% of the river's water and being one of the world's ten largest rivers by average discharge. It originates in Colombia as the Guainía River and flows east-northeasterly through the Puinawai National Reserve before forming the border between Colombia and Venezuela. The river then flows southeast, passing through the towns of San Carlos de Río Negro and San Felipe, and receiving several tributaries, including the Uaupes River, its largest tributary. After passing through the Guyana Shield, the river continues east, forming many large islands and becoming very wide at several locations. It eventually meets the Solimões River to form the Amazon River, creating the phenomenon known as the Meeting of Waters.learn more on wikipedia