Postal History: Europe
A very interesting site showing letters of the 19th century to France from all over Europe. (In French)
A complete and thoroughly written listing of all main postmark types used in France from the beginnings up to 1900; this includes postal marks from the begining to 1830, date postmarks, cancellations from Paris and from the Provinces as well as railway post offices. (In French)
A splendid reference site for anyone interested in the postal history of Russia and related areas. Masses of useful information, displays, discussions, etc. This site is founded and maintained by the Worldwide Society of Russian Philately.