Explanation

• The Great Wall of China was built mainly to protect against invasions from northern tribes like the Mongols.
• It served as a military barrier and lookout system across China's northern frontier.
• Major construction and rebuilding: Ming Dynasty
• UNESCO World Heritage inscription: 1987

Last verified on 12-10-2026

Explanation

• Name: NCSA Mosaic
• Released: 1993
• Developed by: National Center for Supercomputing Applications (NCSA)
• Famous for: Making the World Wide Web popular through its graphical interface.

Explanation

Explanation

• First computer program: Ada Lovelace’s algorithm (1843) for Charles Babbage’s Analytical Engine.
  • First widely used high-level programming language: FORTRAN (1957).
  • Machine Language: The earliest machine-level programming language, using binary 0s and 1s.

Explanation

• The United States established the U.S. Space Force on December 20, 2019.
• It became the sixth branch of the U.S. Armed Forces.
• The Space Force operates under the Department of the Air Force, alongside the U.S. Air Force.
• Its main role is to organize and conduct military operations related to space and space-based capabilities.

Last verified on 07-10-2026