Here is a concise summary of the provided text:
**Title:** Could Megalodon Still Be Alive in the Mariana Trench?
**Summary:**
* The existence of Megalodon, a massive prehistoric shark thought to be extinct 2.6 million years ago, is explored in the context of recent reported sightings in the Mariana Trench.
* While science confirms Megalodon's extinction, the discovery of the giant squid in 2006, previously believed to be mythical, raises the possibility that unknown species might still exist in deep, unexplored ocean areas.
* The Mariana Trench's extreme conditions (constant darkness, high pressure, and unique organisms) could potentially support life, but adapting to these conditions would require significant evolutionary changes in a Megalodon.
* Speculation about a trench-dwelling Megalodon includes bioluminescence, a changed diet, and potentially living for hundreds of years.
* The depth and inaccessibility of the Mariana Trench, with only three people having reached its lowest point, mean that the possibility of unknown species, including a surviving Megalodon, cannot be entirely ruled out without further research.
* The area is now a protected zone, requiring authorized research permits.
Here are the key facts extracted from the text, without opinions, with each fact numbered and in short sentences:
**Megalodon Facts**
1. Megalodon sharks are considered extinct by science.
2. Megalodon existed as early as 23 million years ago.
3. Fossils prove the existence of Megalodon.
4. The name "Megalodon" means "big tooth".
5. Recovered Megalodon fossil teeth are typically 4-5 inches, with some over 7 inches.
6. Megalodon's bite was estimated at 24 to 40,000 pounds of force, stronger than a Tyrannosaurus Rex's.
7. Megalodon is thought to have gone extinct 2.6 million years ago.
8. Megalodon could grow up to 60 feet, three times the size of a Tyrannosaurus Rex.
**Giant Squid Facts**
9. The Giant Squid was once thought to be extinct or mythical.
10. The Giant Squid's existence was confirmed through bodies washing ashore and marks on whales.
11. The first filmed encounter with a Giant Squid occurred in 2006 by Japanese researchers.
12. The Giant Squid is the largest invertebrate on Earth, reaching 59 feet and weighing nearly a ton.
**Mariana Trench Facts**
13. The Mariana Trench is the deepest part of the ocean and the deepest spot on Earth.
14. The Mariana Trench is nearly seven miles deep and over 1,500 miles long and 43 miles wide.
15. Only three people have descended into the Challenger Deep, the lowest point in the trench.
16. The pressure in the Mariana Trench reaches up to eight tons per square inch.
17. The trench has vents releasing hydrogen sulfide and other minerals at temperatures of up to 572°F.
18. Despite extreme conditions, thousands of species of invertebrates and fish inhabit the trench.
**Exploration and Conservation Facts**
19. James Cameron is one of the three people to have reached the Challenger Deep (in 2012).
20. The Mariana Trench is now a U.S. protected zone.
21. Research requests for the area must go through the U.S. Fish and Wildlife Service and the Federated States of Micronesia.