Vacheron Constantin, the oldest continually operating Swiss watch brand, just revealed the world’s most complicated wristwatch. The Les Cabinotiers Solaria Ultra Grand Complication is a double-sided technological feat that took eight years of research and development.

It boasts a record-setting 41 complications, including five astronomical functions—one of which is the first of its kind. And it was all developed, engineered, and assembled by a single master watchmaker.

Vacheron Constantin has filed 13 patent applications for this watch, whose new movement, Caliber 3655, consists of a mind-boggling 1,521 hand-assembled, hand-finished components. In fact, just the assembly of the movement itself (the engine of the watch) took almost a year to complete. In addition to the five astronomical complications that have never been combined in a wristwatch before, it also features a specially-conceived minute repeater with Westminster chime (which sounds the time on demand using four hammers and four gongs in different tones), for which seven of the 13 patents were filed.

Crafted in 18-karat white gold, the round timepiece is remarkably wearable at 45 millimeters in diameter and 14.99 mm in thickness. In fact, the main directive to the watchmaker (Vacheron Constantin won’t divulge his name) from brand executives was to “create something extraordinary but in a compact wristwatch,” says Christian Selmoni, Vacheron Constantin’s style and heritage director. The movement itself measures 36mm in diameter and just under 11mm in thickness. As such, the watch is hailed by the brand as a masterpiece in the art of miniaturization.

“To fit so many complications and components inside is a fantastic feat,” says Selmoni. Putting 41 complications into a timepiece “without rethinking the entire structure would mean a pretty big, pretty thick watch. Making it as compact as possible was a huge driver for innovation.”

So, what exactly can you do with this watch?Well, imagine tracking the tides, the position of the sun and the moon throughout the day, and even having the ability to find a particular star at night, all on the wrist. There’s also a Gregorian perpetual calendar, three lunar indications, including an astronomical moon phase indicator with the age of the moon displayed, a tourbillon escapement (to compensate for errors in timekeeping caused by the effects of gravity when the watch is in certain positions on the wrist) and a 24-hour second time zone and world time indications.

The technologically advanced movement’s unique architecture allows for three ways of telling time: civil (the 24-hour day), sidereal (the actual time—23 hours, 56 minutes and 4 seconds—it takes for the Earth to fully rotate on its axis while revolving around the sun), and solar, or tropical, time (the time it takes for the sun to return to a certain position). All of these times vary throughout the year. The differential is called the equation of time, which is also displayed on the watch.

There are also five highly specialized astronomical complications (among the 14 astronomical complications on the watch) with three patents pending that offer information about the path of the sun. One innovation is a world-first: a celestial sky chart that lets the wearer locate when a specific star or constellation will appear in the night sky. This temporal tracker is linked in the mechanism to the watch’s split-seconds chronograph (that allows for timing multiple events with different end times) and the subject of one of the patent applications.

Another patent is for what the brand is calling the “plug and play” system, which was years in the development process. While not counted as one of the 41 complications, it’s an ingenious development designed to simplify the servicing of the watch.

“This system at the heart of the movement was created so that when the owner has to service the timepiece, the watchmaker doesn’t have to remove multiple hands or dials or complications. It is a sort of module that can be unplugged,” says Selmoni. “It was designed to save days and days of work in servicing.”

According to Selmoni, one of the fantastic aspects of this world’s most complicated wristwatch is the functions’ readability. “Our watchmaker, who is also an engineer, designed every dial, every indication so that it would be very easy to read. This is absolutely not easy to do. He had to reinvent the layout of the functions, create a new camsystem and even design a new case to fit the movement the way he envisioned.”

Of course, Vacheron Constantin, 270 years old this year, is no stranger to the world of record-setting complicated watches. Just last year it unveiled the Berkley Grand Complication double-sided pocket watch with 63 complications. It has also created multiple highly complexwristwatches in recent years, such as the Les Cabinotiers Celestia Astronomical Grand Complication 3600 in 2017 with 23 complications and the Les Cabinotiers Grand Complication Split-Seconds Chrono Tempo from 2020 with 24 complications. Each of those watches measured 50mm in diameter and 20mm or more in thickness.

The Les Cabinotiers Solaria, though, breaks not only Vacheron Constantin’s records, but the records of other top brands, as well. The watch is a unique piece, though Selmoni says he hopes that another rendition or two might be made in a different case material or with different dial colors. And the price? The Swiss manufacturer isn’t disclosing that. Previous highly complicated wristwatches from Vacheron Constantin often carried price tags of upwards of $2 million, and those had way fewer complications and patents filed.