You can see some amazing things while scuba diving.
It's a totally different world down there, actually two totally different worlds depending on whether you do a day or a night dive.
I once did an inland cave dive near Veradero Cuba. The water was 55 feet deep. The interesting thing about the dive is that there was a thermoclime. This can be a result of an extreme difference in water temperature from one body of water to another, or in this case the first 30 feet of the dive was fresh water and the bottom 25 was salt water.
It is one of the few places in the world where the water gets warmer the deeper you go.
Between the 30 foot mark and the 40 foot mark visibility is only a couple of feet, anything above or below the thermoclime is crystal clear.
Pretty neat stuff.