The Mississippi River meets the Gulf of Mexico. The two
bodies of water never mix with each other; allowing the
Gulf of Mexico to retain its clear, blue color. Simply
amazing!


Source: http://36trends.com/god-great-see-amazing-photos-river-meets-another/

Allahu Akbar! amazing sight! Wish to there one day.
BTW this is one of the miracles of the Holy Quran it described the phenomenon 1400 years ago, amongst other scientific facts which are only discovered centuries later.
The Holy Quran mentioned that there is a barrier between two seas that meet and that they do not transgress. God has said:
He has set free the two seas meeting together.
There is a barrier between them. They do not
transgress. (Quran, 55:19-20)
But when the Quran speaks about the divider between fresh and salt water, it mentions the existence of “a forbidding partition” with the barrier. God has said in the Quran:
He is the one who has set free the two kinds of
water, one sweet and palatable, and the other
salty and bitter. And He has made between
them a barrier and a forbidding partition.
(Quran, 25:53)