Alexander the Great, when he went to India, saw a large reptile which was over 30 metres long, that the Indians kept in a cave. See the paragraph: Dragons in India and the paragraph: Alexander and the Dragon.
Many ancient sailors have reported seeing sea serpents. 
These could be plesiosaurs and mosasaurs which were like huge lizards or crocodiles with flippers or webbed feet. They probably swam in a snake-like motion.
Georg von Forstner a German submarine Captain in World War I reported this:
“…the description of an animal estimated at 20 metres in length, seen by me and some of the crew of the submarine U28 on 30 July 1915 in the Atlantic Ocean; [it] was sighted on the starboard side, about 60 nautical miles south of Fastnet Rock, off the southwest corner of Ireland, after the sinking of the British steamer Iberian. This animal was hurled some 20 or 30m into the air by an underwater explosion about 25 seconds after the sinking of that vessel, thrown full length from the water. It is possible that this was caused by the detonation of an explosive device on board, the existence of which we assumed was concealed in the ship’s papers, or from a small boiler explosion… This explosion certainly could have been the result of a detonation, but in my opinion only the bursting of the spaces deep inside the ship could have produced such air pressure.
The animal was about 20 meters long and crocodile-like in shape, with pairs of strong front and hind legs adapted for swimming, and a long head that tapered towards the nose…
Our senior engineering officer, marine engineer Romeihs, watched the animal for 10 to 15 seconds at a distance of about 150 to 100m in bright sunshine with the aid of powerful glasses.” 
The opponents of this account are skeptical of the size of the ‘crocodile’ – but Forstner only says that it is ‘crocodile-like’ which means it doesn’t have to be a crocodile.
Also they question the legs which to them means that they they couldn’t be fin-like, but Forstner says they were ‘adapted for swimming’ which suggests that it had fins or webbed feet.
Another argument is that none of the survivors of the sunk ship wrote about seeing a sea creature (some did write about the sinking of their ship and their escape), but surely, if this creature had really appeared at that moment, they would have been so filled with grief for their lost mates and fearing for their own lives, that seeing a sea creature would seem almost irrelevant to write about it during a war.
In a Welsh book on folk stories (1909) it tells of an old
“The woods around Penllyne Castle, Glamorgan, had the reputation of being frequented by winged serpents, and these were the terror of old and young alike.
They were the terror of old and young alike.
An aged inhabitant of Penllyne, who had died a few years ago, said that in his boyhood the winged serpents were very beautiful. They were coiled when in repose ‘and looked as if they were covered with jewels of all sorts. Some of them had crests sparkling with all the colours of the rainbow’. When disturbed they glided swiftly, ‘sparkling all over’ to their hiding places. When angry, they ‘flew over people′s heads, with outspread wings, bright, and sometimes with eyes too, like the feathers in a peacocks tail.’ He said it was ‘no old story invented to frighten children’ but a real fact. His father and uncle had killed some of them, for they were ‘as bad as foxes for poultry’. This old man attributed the extinction of the winged serpents to the fact that they were ‘terrors in the farmyards and coverts’.” 
In the Bible there is this description of a Dinosaur-like creature:
“Look at the behemoth, which I made along with you and which feed on grass like an ox. What strength he has in his loins, what power in the muscles of his belly! His tail sways like a cedar; the sinews of his thighs are close-knit. His bones are tubes of bronze, his limbs like rods of iron. He ranks first among the works of God.” 
This was probably written about 4000 years ago, (after the worldwide flood of Noah′s time). Here God describes a giant, plant eating land animal (possibly the Diplodocus or Apatosaurus). Some people say that this description is of an elephant or a hippopotamus, but they do not have tails like the thick, massive trunks of cedar trees!
So could dinosaurs have lived with mankind down through the ages?
We can′t say for definite, but the above reports, plus lots of historic art work, drawings, pottery, etc, all point to the exciting possibility that dinosaurs have lived at the same time as mankind.
Many dinosaur species must have died out when the earths climate changed, but not all of them!
For lots more information see the website: ChristianAnswers
Watch the video The Great Dinosaur Mystery (Produced by Eden Communications/Films for Christ)
And get the book The Great Dinosaur Mystery and the Bible by Paul S. Taylor which contains more information (especially biblical) not discussed in the film.
Here is an expanding list of further articles:
- Creation or Evolution – does it really matter?
- Humans and dinosaur’s together? Part 1 Did the dinosaurs really become extinct 65 million years ago? See some evidence that suggests; ‘No!’
- (This article) Humans and dinosaurs together? Part 2
- Are dragons real creatures?
- Understanding fossils: Are fossils as old as evolutionists claim them to be? How easy is it to investigate the bones, & what did dinosaurs look like?
- Accuracy of Fossil Dating Methods Part 1. What is Radiometric Dating? Are dates manipulated?
- Accuracy of Fossil Dating Methods Part 2. Wrong dates for a known age of rock. Is the Isochron dating technique “foolproof”?
Do all the different dating methods agree? How carbon 14 creates a problem for evolutionists.
- The Standard Geological Column: That everyone can agree on.
- How quickly do rock layers form? Answer: A lot quicker than we are led to believe. Are there transitional fossils?
- The earth’s catastrophic history: Very rapid, deep burial of fossils. A widespread erosion surface: The Great unconformity. Eustatic sea levels.
- Millions of years gaps: Paraconformities. Colonized sea-floors (hardgrounds).
- Fossil tracks, dinosaur eggs and nests. What are the first tracks to be found in the fossil record and why?
- Explaining the fossil record. Why that particular order of fossils? Imagine this scenario….
- Fossil Chart to accompany the article above ‘Imagine this scenario’
- The horror of the flood as recorded in the Bible.
- Some facts & figures about Noah’s Ark. Would the ark have been sea worthy?
- Could Noah have built such a huge ship?
- Other Flood stories from around the world.
- Could the earth be 1000’s of years old, and not billions of years?
 Sea serpents Wikipedia
 Von Forstner’s own account [Begegnungen pp.9-10], he published in the Deutschen Algemaine Zeitung.
 Trevelyan, Marie, 1909, Folk-Lore and Folk Stories of Wales, 1909
 Job 40:15-19 (NIV)