- Ancient Innovations (up to 500 AD)
    ├── Wheel (c. 3500 BC)
    ├── Writing Systems (c. 3200 BC)
        ├── Cuneiform (Sumerians, c. 3200 BC)
        ├── Hieroglyphs (Egyptians, c. 3200 BC)
    ├── Bronze Metallurgy (c. 3300 BC)
    ├── Iron Metallurgy (c. 1200 BC)
    ├── Water Clocks (c. 400 BC)
    └── Printing (Woodblock, c. 200 AD in China)

- Medieval Innovations (500 AD - 1500 AD)
    ├── Windmills (c. 7th century AD)
    ├── Mechanical Clocks (c. 13th century AD)
    ├── Eyeglasses (c. 1286 AD)
    └── Gunpowder (c. 9th century AD in China, 13th century in Europe)

- Renaissance & Early Modern Innovations (1500 AD - 1800 AD)
    ├── Printing Press with Movable Type (c. 1450 by Johannes Gutenberg)
    ├── Telescope (1608 by Hans Lippershey, though Galileo's version in 1609 is more famous)
    ├── Steam Engine (1712, Newcomen's atmospheric engine)
    └── Lightning Rod (1752 by Benjamin Franklin)

- 19th Century Innovations
    ├── Electric Telegraph (1837, first practical version by Samuel Morse)
    ├── Photography (1839, first practical photographic process by Louis Daguerre)
    ├── Telephone (1876 by Alexander Graham Bell)
    ├── Electric Light Bulb (1879 by Thomas Edison, though there were earlier versions)
    └── Automobiles (1885-1886, Benz Patent-Motorwagen by Karl Benz)

- 20th Century Innovations
    ├── Airplanes (1903, Wright brothers' first powered flight)
    ├── Computers (1930s-1940s, depending on definitions; Konrad Zuse's Z3 in 1941, ENIAC in 1945)
    ├── Internet (1960s-1970s, ARPANET established in 1969)
    ├── DNA Double-Helix Model (1953 by James Watson and Francis Crick)
    └── Space Travel (1961, Yuri Gagarin first human in space)

- 21st Century Innovations 
    ├── Human Genome Project Completion (2003)
    ├── CRISPR for Gene Editing (2012 by Jennifer Doudna and Emmanuelle Charpentier)
    ├── Quantum Computing Advances (various milestones, e.g., Google's "quantum supremacy" in 2019)
    └── Artificial Intelligence & Deep Learning Breakthroughs (e.g., DeepMind's AlphaGo in 2016)