Czech painter Alphonse Mucha produced a series of 20 magisterial paintings covering the history, religion and mythology of the Czechs. They were produced from 1910 to 1926 and are as large as 26 by 20 feet. They have not had a permanent home but now a new museum is under construction in Prague to house the massive paintings.
The best place to see the images are at Epopaj, where a new book on the Slav Epic paintings is being produced from high-res scans.
The Mucha Foundation also has a good collection of images.
The Creative Adventurer has a good article and photos of the installation.
Below are some videos of the last public exhibition of the paintings.
This video has some explanation of the paintings.