Now open — although still under construction — is a vast and remarkable project, Pfaffenthal 1867, sponsored by the Luxembourg National Museum of History and Art and the Luxembourg City History Museum, and managed inworld by Hauptmann Weydert. It isn't, by any measure, the first attempt to recreate a historical location in Second Life, but it is possibly the most ambitious, spanning (eventually) eight sims. Using historical maps (see here for an example), the sims attempt to replicate in detail Pfaffenthal, a quarter in nineteenth-century Luxembourg City described in the introductory notecard as "a hotbed, stirring with a rich diversity of professions, cultures and languages" — 1867 being the year the small nation achieved its independence.
The wearing of period attire is requested, and free outfits for both ladies and gentlemen are available at the landing point, along with general information about the Pfaffenthal project. From the welcome area, visitors step directly into the street, flanked by Max Menager's bakery and the Friperie Heintze, a second-hand clothes shop, and from there can begin to explore the narrow crooked avenues that can turn at disorientingly odd angles, and discover more of the city that lies across the river. If you fan out, leaving the old town behind, you'll begin to find many areas — almost entire sims — that for now are simply outlines or blueprints of what is to come, and it will certainly be fascinating to watch the construction unfold.
Pfaffenthal is poetically quaint, and it's a great pleasure to simply wander its streets and alleys, admiring the diverse architecture and the ways in which light slices into alleys and glances off walls. If you're truly fascinated, then it's a potential home, as Hauptmann and his colleagues invite people to take on roleplay characters within Pfaffenthal, and you can live there rent-free, with certain restrictions — many of the homes, shops and other locations such as churches are fully furnished. (Hauptmann is delighted to chat with all visitors — he may well come running up to greet you — and is an excellent and enjoyable source for more information.)
The project is an extension of the virtual Fort Thüngen that has run in the sim Kirchberg since 2012 (image below), and now one of the eight sims in the project. For individuals lucky enough to visit the real life Musée d'Histoire de la Ville de Luxembourg, it's also possible to visit Pfaffenthal from within the museum using the Oculus Rift — read more here. So you might encounter someone operating an avatar from within the museum — keep in mind that the process may not be easy for them. (And sometimes a few avatars are stationed about, performing various tasks.) Contributions are welcome.