January 4, 2012: 98-night world circumnavigation cruise on P&O Cruises is a round-trip from Southampton, England. Follows the traditional westward route around the world.
January 5, 2012: 109-day world cruise on Seabourn from Fort Lauderdale to Venice, Italy. Ultra-luxury cruise on the Seabourn Quest sails an unusual route.
January 6, 2012: 112-day world cruise on Holland America is a round-trip from Fort Lauderdale, Florida. A westward route around Cape Horn to Antarctica, the South Pacific, Asia, India, and the Mediterranean.
January 6, 2012: 116-day cruise around the world on Silversea from Fort Lauderdale to Monaco. Another ultra-luxury ship sailing an unusual route.
January 10, 2012: 107-day cruise around the world on Cunard Line is a round-trip from Southampton, England. A luxury trip that follows the traditional westward route through the Panama and Suez Canals.
January 10, 2012: 108-day world cruise on Cunard Line is a round-trip from Southampton, England. Not a true world cruise, this one doesn't visit the Americas.
January 13, 2012: 107-day world cruise on Princess Cruises from Fort Lauderdale to Venice, Italy. Follows the traditional route through the Panama and Suez Canals.
January 18, 2012: Crystal world cruise round-trip from Los Angeles. Not a real world cruise; this voyage goes to Asia, Australia and the South Pacific.
Another long cruise option is a cruise to Brazil from the US.
See our complete coverage of cruises around the world in 2013.