Radio astronomy is largely defined by the continued development of ever more powerful instruments with continually improving sensitivity and unanticipated and vastly better angular resolution. Particularly notable has been the construction of sophisticated radio interferometer and aperture synthesis systems that have up to 1,000 times better angular resolution than the best optical telescope, although radio wavelengths are 100,000 times longer than optical wavelengths. Many radio telescopes have not been used for what they were built for. The Arecibo 1,000 foot dish was designed for ionospheric radar experiments, not for radio astronomy. But theoretical analysis underestimated the strength of reflected radio echoes from the ionosphere, and so a very much cheaper dish would have sufficed for the ionosphere experiments. Nevertheless, the US Air Force, obsessed with anything connected with the ionosphere and incoming Russian missiles, paid for the Arecibo radio telescope to be built as designed. Later, it took a freak accident, an ambitious radio astronomer, and a powerful Senator to secure the funds to build the world’s largest fully steerable radio telescope in Green Bank, WV.