The paper describes the history of the International Association of Geodesy from its forerunner established in 1862 to the Section of Geodesy of the International Union of Geodesy and Geophysics in 1922 and its development to the present. It focusses on five major periods: (1) between the World Wars; (2) re-establishment after World War II; (3) inception of the space age; (4) geodynamic research and scientific services; and (5) the Global Geodetic Observing System (GGOS).

Charles Hutton suggested in 1821 that the pyramids of Egypt be used to site an experiment to improve the estimate of the density of the Earth. He had previously estimated the horizontal attraction of a Scottish mountain as part of Nevil Maskelyne’s 1774 "Schiehallion Experiment". I present a virtual realization of an experiment at the Giza pyramids to investigate Hutton’s concept. I show that such an experiment would indeed have allowed a more accurate mean Earth density to be determined.

The expanding Earth theory holds that the original Earth was much smaller and that ocean basins were lacking then. While the theory has largely been debunked in recent years, new research from GPS and other space geodetic techniques indicates that the Earth may actually be expanding at present at about 0.1–0.4 mm/yr. In addition, new evidence showing that deep mantle plumes rise all the way from the core–mantle boundary sheds light on a possible expansion mechanism.

Early data by pendulum instruments in Norway contributed to the first global gravity system. Spring gravimeters were used for a national gravity database, geoid computation, and for geophysical prospecting. Absolute gravimeters revealed gravity changes caused by land uplift since the last ice age. The first gravity data at sea were obtained in the Arctic Ocean. Current terrestrial and satellite data allow geodynamical studies relevant to climate change, caused by melting glaciers and ice sheets.