Lagoon
A little bit more South, 3 hours away from Guelmim towards the South, about 10 miles after Sidi Akhfénir, there you will find the Naya lagoon (a sign on the right, with a drawing of a pink flamingo, has "Sibe Khenifiss" written on it).
The view from the cliff is breathtaking, wether when the tide is low or high.
Tours of the lagoon on rowboats are also available, you can discover the the multitude of birds living there permanently or during their migration. This site is famous and many ornithologists come to study the birds there.