Caribmap - A cartographic history of the West Indies. This is a great resource if you are running a swashbuckling game or a steampunk game set in the Caribbean. There are dozens op maps for each territory, from 1500 to contemporary maps. The maps cannot be downloaded, but the zoom function shows them in great detail.
For some flavour of the local fauna and flora, check out Caribherp and Caribnature.
A collection of historical maps, right now there's mainly Russia and Asia. The maps can be downloaded as PDFs for free. Don't ask me why, but the English version of the site doesn't give you a download link. But if you click "PDF Download" and then click the German flag on the left, you'll get the download button.
Norway Heritage has a beautiful collection of photos and historical documents illustrating the lives of immigrants. There are photos of immigrant ships, deck plans, immigration papers, passports, tickets, photos from the voyage, from the ports where people left and arrived and much more. It's a wonderful resource whether your folks came from Norway or not and it could be great for a Cthulhu game for example - one set at Ellis Island maybe? Come on, that would be awesome.
Original films from Nazi Germany - some feature films, films from private collections, educational movies, military and otherwise. All uncommented and obviously in German.
My Armoury is a fantastic resource for historic weapons and armour. They have an extensive collection of photos and articles on everything from paper armour to famous battles to certain types of weapon.