1906 - The first aerial photographs of Stonehenge - the first aerial
photographs of any British archaeological monument - were displayed at the
London premises of the Society of Antiquaries.
They were taken from a hydrogen balloon, probably around late September
1906, by 2nd Lieutenant Philip Sharpe of the Royal Engineers' Balloon
Section. The Royal Engineers began using hydrogen balloons in 1878 (not
hot-air), and had been experimenting with aerial photography from at least
1881. The first intentional aerial photo for archaeological purposes was
taken in June 1899, of excavations at the Forum in Rome.