(CNN) -- The most "complicated" handmade watch in the world has been sold at auction for an historic $24.4 million.

The Henry Graves Supercomplication timepiece, made by the luxury watchmaker Patek Philippe in 1933 for the prominent banker Henry Graves, was sold at Sotheby's in Switzerland.

The sale smashed the world record for the most expensive watch ever sold at auction, which was previously held by the same watch. In 1999, it was sold to Sheikh Saud Bin Mohammed Bin Ali Al-Thani of the Qatari royal family, for $11 million.

The watch was released in 2014 to coincide with the 175th anniversary of the Swiss watch maker. The sale has benefited from the boom in Patek Phillippe auction values over the last 15 years.

The term "complication" is a technical one, and refers to any aspect of a watch that offers a function that is not simply telling the time.

The timepiece -- which has been called "the most important watch in the world," "one of the wonders of the world," and "the collector's holy grail" -- boasts 24 such complications.

These include grande and petite sonnerie (chimes), which emulate the bells of Westminster; a record of the phases and age of the moon; sunrise and sunset indications; a "perpetual calendar" that makes automatic adjustments for month and year; and a celestial map of the New York sky.

The celestial map alone is a remarkable feat of engineering. It charts the precise spacing and density of the stars, and rotates at the same pace as the sky as it would have appeared from its owner's Fifth Avenue apartment.

The watch is comprised of 900 individual parts, and, according to Sotheby's, is the most advanced timepiece ever made without the assistance of computers. It was last wound in 1969, yet remains in perfect working order.

The Supercomplication was made as the result of a friendly competition between Graves, a member of a well-known banking family, and James Ward Packard, the luxury automobile manufacturer, to see who could produce the most impressive timepiece.