50 Greatest breakthroughs since the wheel By ADML 4000 BCE The sailboat 3400 BCE The nail 1500 BCE Alphabetization 400 BCE The abacus 260 BCE The lever 250 BCE Archimedes’ screw 105 Paper 618 Paper money 900 Gunpowder 1100 The compass 1248 Optical lenses 1300 The mechanized clock 1436 The Printing Press 1582 The Gregorian calendar 1712 The steam engine 1757 The sextant 1787 Machine clock 1793 The cotton gin 1796 Vaccination 1800 Scientific plant breeding 1824 Cement 1826 Photography 1836 The combine harvester 1837 The telegraph 1837 The moldboard plow 1846 Anesthesia 1850 Refrigeration 1850 Sanitation systems 1856 Industrial steelmaking 1858 Oil refining 1859 Oil drilling 1860 The internal combustion engine 1863 Pasteurization 1876 The telephone 1878 Electric light bulb 1884 The steam turbine 1886 The automobile 1895 Radio 1902 Air-conditioning 1903 The airplane 1913 The assembly line 1918 Nitrogen fixation 1926 Rocketry 1927 Television 1928 Penicillin 1939 Nuclear fission 1959 Semiconductor transistor 1960 The pill 1960 The Internet 1965 The green revolution 1974 The personal computer
