Arnim Jenett (Janelia Farm Research Campus), Kazunori Shinomiya, Kei Ito (both Tokyo University), and other anatomists made a great site with a 3D-viewer of adult Drosophila brains available. You have the chance to scroll threw a whole mount stack while ticking different brain areas. Those brain areas are listed next to the stack. Different areas are coloured differently, so that you can look at the location of several areas in the same brain. On the main page you can find simply explained tutorials about the usage of the site. It is correlated to the anatomical search engine of the Janelia farm GAL4 collection.
Because it was very helpful to me to learn all the synonyms of relevant areas and because I think it is very helpful to learn more about the structure of the Drosophila brain in general I wanted to advertise the site here.
https://www.virtualflybrain.org/site/vfb_site/overview.htm