They're the opposite of a three-hour tour.
High-end cruise line Silversea has announced a series of super-long voyages for autumn 2013, including two 40-day trips, as well as some even longer sails. Serious cruisers can now test their endurance with a 54-day trek from Istanbul to Barbados, with stops at many Mediterranean ports.
The trips obviously don't come cheap. A 40-day sail from Hong Kong to Auckland with stops throughout Southeast Asia starts at $15,940 per person. A 41-day trip from Athens to Fort Lauderdale starts at $14,781 per person. A 40-day journey from Barbados, around Cape Horn and to Santiago starts at $17,526 per person.
Amazingly, these aren't the longest trips that Silversea offers. One of the line's ships will set sail on a 113-day, 54-port world sail on January 6, 2014.
Silversea isn't the only luxury line to offer the extended journeys. Seabourn has an upcoming 32-day sailing from Hong Kong to Dubai that stops at a number of exotic Asian ports. Celebrity offers an 18 day trip across the South Pacific that is only brief in comparison.