Here is a concise summary of the provided text, focusing on the main discoveries and attractions:
**Underwater Discoveries and Attractions:**
1. **San Jose Galleon**: A Spanish shipwreck off Colombia's coast, containing treasures worth ~$20 billion.
2. **Underwater River (Yucatan, Mexico)**: A natural phenomenon where fresh and salty water don't mix, creating a visible "river" at 30m depth.
3. **Yonaguni Monument (Japan)**: A debated structure at 26m depth, with some attributing it to ancient civilizations, while scientists consider it a natural formation.
4. **Lion City (China)**: An ancient, well-preserved city at ~20m depth, discovered in 2001, with visible architecture and artifacts.
5. **Baltic Sea Anomaly**: A mysterious, large object resembling the Millennium Falcon, later revealed to be a natural rock formation, though its discoverers remain skeptical.
6. **Heraklion (Egypt)**: An underwater city at ~10m depth, with ruins dating back ~14,000 years, discovered in 1999.
7. **Luminous Spiral (Australia)**: A massive, living colony of siphonophores, approximately 47m long, discovered in 2020.
8. **Antikythera Mechanism (Greece)**: An ancient analog computer (~100-150 BCE) found in a Roman shipwreck, used for astronomical calculations.
**Other Notable Mentions:**
* A giant jellyfish (15m diameter) spotted in British seas.
* A massive anaconda filmed in a Brazilian river.
* Gorda Cave (Ural Mountains), featuring one of the longest underwater tunnels (~48km) with exceptionally clear water.
Here are the key facts extracted from the text, without opinions, in short sentences with numbers:
**San Jose Galleon**
1. The San Jose was a Spanish galleon found near the Colombian coast.
2. The ship sank on July 8, 1708, at a depth of approximately 6 kilometers.
3. The treasure on board was valued at approximately $20 billion.
4. The treasure was intended for King Philip IV of Spain.
**Underwater River (Yucatan Peninsula, Mexico)**
5. An underwater "river" was discovered at a depth of 30 meters near the Yucatan Peninsula.
6. The phenomenon is caused by a funnel with freshwater on top and salty underground water below.
7. The difference in density prevents the waters from mixing.
**Yonaguni Monument (Japan)**
8. The Yonaguni Monument is a stone structure located at a depth of 26 meters.
9. The structure measures approximately half a football field in size (around 5000 years old).
10. Some believe it's a natural formation, while others think it's man-made.
**Lion City (China)**
11. Lion City is an underwater city located at a depth comparable to a subway car's length.
12. The city was flooded in 1959 to build a hydroelectric plant, creating Qiandao Lake.
13. The site was rediscovered in 2001 by divers and is now popular among experienced divers.
**Baltic Sea Anomaly**
14. An unidentified object was found in the Baltic Sea in June 2011.
15. The object is approximately the length of a hockey rink.
16. Scientists determined it's a natural rock formation, part of a glacier.
**Heraklion (Egypt)**
17. Heraklion is an underwater city located at a depth approximately equal to a school bus's height.
18. The city is at least 14,000 years old.
19. French underwater archaeologist Franck Goddio discovered the ruins in 1999.
**Luminous Spiral (Western Coast of Australia)**
20. A luminous spiral, approximately 47 meters long, was discovered in 2020.
21. The spiral is a colony of siphonophores, a type of sea creature.
**Antikythera Mechanism (Greece)**
22. The Antikythera Mechanism is an ancient analog computer discovered in 1901.
23. The mechanism consists of about 30 bronze gears, used to track celestial movements.
24. It's dated between 100 and 150 years BC.
**Giant Jellyfish (British Seas)**
25. A giant jellyfish, approximately 15 meters in diameter, was discovered.
26. It's considered the largest jellyfish ever found in British seas.
**Gorda Cave (West of Ural Mountains)**
27. Gorda Cave has an underwater tunnel system extending for 48 kilometers.
28. The water in the cave is crystal clear, with visibility up to 46 meters.