This is the closest we have to a monster game, mostly in terms of its length. It is a strategic and operational scale game of the central European theaters of the Napoleonic Wars, with expansions to add Spain, Russia, Scandinavia, Central Mediterraneon and the Ottoman Empire (western half).
There are multiple scenarios in the game (see Scenario Booklet for full list): 1805 (vs Austria, Britain and Russia), 1806-07 (vs Prussia, Britain and Russia), 1805-1807 (vs all four), 1809 (vs Austria, Russia and Britain), 1813-1815 (vs all four), and 1815 (the 100 days of Napoleon's second reign). Some scenarios are suitable for 2-5 players. A player-turn takes about 5-15 minutes, so along with a strategic turn, a full "season" (two months is the length of a strategic turn and its associated operational turns) takes about 1.5 - 2.0 hours - less if there are no battles, more if there are many big battles.