Some of the world's priciest real estate floats on open waters

The residences start at 290 square feet and run up to about 3,500 square feet, with prices ranging from $1.8 million to $15 million

It’s among the world’s most-expensive real estate per square foot, where the oceanfront views never tire, and where the price of entry buys access to the otherwise inaccessible—165 apartments aboard The World, a condo cruise ship. Its intensely private residents spend a third of the year, on average, gliding to the planet’s farthest reaches: Antarctica, Pacific atolls that haven’t seen a ship in two decades, and Ascension, a volcanic outcropping halfway between Africa and Brazil.

It took Trevor Rowe, chairman of Rothschild Australia, fewer than 72 hours to decide to buy a two-bedroom unit in 2012. At 1,391 square feet, the