Photogrammetric air surveys have been made of Stonehenge, the Great Temple of Amon-Re, Karnak, and the desert lines near Nasca, Peru. The latter designs have been correlated in time with pottery of type Nasca 3 and 4. New astronomical alinements have been found for the trilithons and station stones at Stonehenge. The Amon-Re temple alined precisely, within the limits of present-day measurements, with the rising of the Sun at midwinter at the time of rebuilding of the structure by Tuthmosis III. No significant astronomical alinements were found for the desert lines. The possible significance of the British and Egyptian alinements are discussed together with the implications of the negative result in Peru. Some comments are made concerning the precision of the megalithic yard, and the geometries and stellar alinements of prehistoric British structures.