North and South Yemen have been visited several times, the images were taken between 1991 and 1998. The analogue archives contain - including images taken by another traveler in 1986 - more than 2000 slides and black & white negatives.
In addition rare historical images from the 1940s, 1950s and 1970s taken by Eva Hoeck und Erich Holm von Prosch exist, they can be found here Historical Images