The Coelacanth (Latimeria chalumnae) was thought to be extinct for more than 60 million years until a live specimen was captured in 1938. We now know that there is a small but definitely surviving population of these ancient fish in very deep waters off eastern Africa and another was recently discovered off Indonesia. Who's to say that Megalodon does not also survive?
95% of our oceans are unexplored...consider the possibility that such a creature could still exist and still lurking the depths of the deep..
One well-known example was reported by writer David G. Stead in his book Sharks and Rays of Australian Seas, that was released in 1963. The brief excerpt of this account is mentioned below:
In the year 1918 I recorded the sensation that had been caused among the “outside” crayfish men at Port Stephens, when, for several days, they refused to go to sea to their regular fishing grounds in the vicinity of Broughton Island. The men had been at work on the fishing grounds—which lie in deep water—when an immense shark of almost unbelievable proportions put in an appearance, lifting pot after pot containing many crayfishes, and taking, as the men said, “pots, mooring lines and all”. These crayfish pots, it should be mentioned, were about 3 feet 6 inches [1.06 m] in diameter and frequently contained from two to three dozen good-sized crayfish each weighing several pounds. The men were all unanimous that this shark was something the like of which they had never dreamed of. In company with the local Fisheries Inspector I questioned many of the men very closely and they all agreed as to the gigantic stature of the beast.
This report actually got considerable attention from the media and David G. Stead himself believed in this account. But most shark experts through careful examination of this account, pointed out some clear signs of exaggerations at several points (including the size factor) and questioned the authenticity of this account, because the sailors themselves were giving contradictory statements. Hence, those sailors were most likely exaggerating the details of that event. One expert even said that those sailors might have concocted this story, after they lost their crab pots in an accident.
Another well-known account was reported by writer Zane Grey and his son Loren in 1933. His actual comments have been narrated by Gross in 1987:
At first I thought it was a whale, but when the great brown tail rose in the ship’s wake as the fish moved ponderously away from the liner, I knew immediately that it was a monstrous shark. The huge round head appeared to be at least 10 to 12 feet across if not more … It was my belief that this huge, yellowish, barnacled creature must have been at least 40 or 50 feet long. He was not a whale shark: the whale shark has a distinctive white purplish green appearance with large brown spots and much narrower head. So what was he—perhaps a true prehistoric monster of the deep? 
After careful examination of this case as well, most shark experts concluded that Grey’s description of the animal still closely matches that of the whale shark and he is wrong about the coloring of this animal. An expert, Castro, gives a good explanation of the coloring of the skin of whale sharks. He points out that many white or yellowish spots can be observed on the skin of whale sharks. And it is clear that a whale shark has a very wide, squarish, yet slightly rounded head.
In fiction and popular culture
Ever since the remains of this shark were discovered, it has immensely fascinated people. In the past, people used to think that the oceans were inhabited by dangerous monsters big enough to destroy boats and could be regarded as serious threats to fishers. C. megalodon has made its way onto the list of such monsters.