Explanation

• First Polio Vaccine Introduced: 1955
• Developer: Dr. Jonas Salk
• Type: Inactivated Polio Vaccine (IPV)
• Oral Polio Vaccine (OPV): 1961
• Developer of OPV: Dr. Albert Sabin

Last verified on 20-07-2026

Explanation

• Country: China
• First use: 806 AD (approx.)
• Early name: Feiqian (Flying Money)
• Dynasty: Tang Dynasty → Song Dynasty (official issue)
• Importance: First-ever paper-based monetary system

Last verified on 11-06-2026

Explanation

• Country: Australia
• Name: Great Barrier Reef
• Location: Coral Sea, off Queensland
• Length: Over 2,300 km (1,400 miles)
• Area: Approximately 344,400 km² (133,000 sq mi)
• The reef consists of around 2,900 individual reefs and 900 islands.
• It is a UNESCO World Heritage Site, inscribed in 1981.

Last verified on 20-07-2026

Explanation

• Launched: 7th September 2013
• Founder / Initiator: Xi Jinping
• Main Goal: Global connectivity through roads, railways, ports, and energy projects
• Regions Connected: Asia, Europe, Africa, and beyond
• Participating Countries: Over 150 countries

Last verified on 10-03-2026

Explanation

• Venezuela has the largest proven oil reserves in the world.

Additional information:

1. Venezuela – ~303 billion barrels
2. Saudi Arabia – ~267 billion barrels
3. Iran – ~209 billion barrels
4. Canada – ~163 billion barrels
5. Iraq – ~145 billion barrels

Last verified on 20-07-2026