Robert Greubel and Stephen Forsey have shown creative daring and boldness in uniting their second Fundamental Invention, the Quadruple Tourbillon, with their groundbreaking interpretation of the GMT with its outsized rotating globe. Robert Greubel —a former IWC employee that worked on their Grand Complication Project and prototypist for complications at Renaud & Papi— and Stephen Forsey have been working together for over 20 years. In 1992, Stephen met Robert at Renaud & Papi, and in 2001 they co-founded 'Complitime', a company focused on developing and crafting complicated movements for prestigious brands. In 2004, Robert and Stephen unveiled 'Greubel Forsey' and amazed watch collectors around the world with their innovative Double Tourbillon 30-degree.

Displaying three time zones along with a universal time function, this exceptional timepiece is distinguished by its three-dimensional architecture created with extreme attention to fine craftsmanship and is one of the most fascinating world timer complications I have ever reviewed in the metal.

But what makes the Greubel Forsey GMT Quadruple Tourbillon Titanium so special? Well, a little bit of everything. From the complications to the finishes, there’s something special about this watch throughout the whole piece and I’ll talk more about it.

The Greubel Forsey GMT Quadruple Tourbillon brings several complications into one incredible timepiece that include a second time zone, a rotating globe with universal time with 24 time zones, a day/night indicator, the indication of those cities observing summer time, a lateral window showing the equator and southern hemisphere, a power reserve indicator and a quadruple tourbillon —double tourbillons at 6 and 11 o’clock. Pretty much anything that a globetrotter or man of the world would need.

In bringing the Quadruple Tourbillon and the GMT mechanisms together, Greubel Forsey not only accomplished a major technical feat that led to the creation of a new manual wound calibre comprising 805 parts and including three fast-rotating barrels.

With a multi-layer three-dimensional construction expressed on many levels, the GMT Quadruple Tourbillon in titanium features a three-dimensional terrestrial globe that provides an intuitive picture of time all over the world in a distinctive asymmetrical titanium case measuring 46.5 mm in diameter and 17.45 mm in thickness. Once you see this watch in the metal is when you realize the complexity of every component and the attention to detail that has been given to it.

The sapphire crystal opening on the case band at 7 o'clock allows for a full view of the delicately matte-finished terrestrial globe which indicates those areas of the world where it is daytime. The terrestrial globe makes one complete rotation every 24 hours anticlockwise —the Earth’s natural rotational direction viewed from the North pole— and the position of the continents can be easily cross-referenced with the time on the equatorial chapter ring which is marked with 24 time zones and day/night indication. But foremost, what makes this watch so special is the level of finishing throughout the whole watch. I cannot find a single flaw in the finishes or any rough spots on any of the components. Of course this is a watch priced closed to one million dollars, but I’ve seen flaws on other watches from other brands within a comparable price range.

A dual-function pusher located on the left caseband at 4 o'clock position with GMT engraved on it, allows for quick setting of the second time zone that is indicated on a small register at 4 o'clock as well as adjustment of the rotating globe that is synchronized with a cities disc on the back of the watch. The dial features a 72-hour power reserve indicator at 3 o'clock superimposed on the blue hours ring and the local time is shown on the off-centered subdial at 12 o'clock.

Turning the watch over reveals another exciting part of this watch that is almost as fascinating as the front. The display case back allows for full view of a worldtimer disc with 24 cities providing the traditional way of reading time in multiple time zones as well as the indication of cities observing summer time. As the cities disc rotates, so does the terrestrial globe to perfectly show night and day areas of the earth. Those cities not using DST have a dark background and time is read on the outer chapter ring.

The beating heart inside this watch is composed of 705 parts with three series-coupled fast-rotating barrels —1 turn in 3.2 hours—, one of which is equipped with a slipping spring to avoid excess tension. There are four tourbillon cages composed of 260 parts and with a total weight of 2.25 grams. The main plates are nickel silver, frosted and spotted with polished bevelling and countersinks, straight-grained flanks, and nickel-palladium treatment. Bridges are black polished which is one of the signature finishes that Greubel Forsey excels at. Inned tourbillons are inclined at a 30-degree angle and perform a rotation per minute. Meanwhile, the outer tourbillons perform a full rotation every four minutes. And the black polishing on all the bridges and throughout the movement is simply out of this world.

This fascinating piece of horology is fitted with a beautiful and very comfortable blue rubber strap with deployant buckle. Opposed to it’s somewhat thick and bulky construction, the GMT Quadruple Tourbillon Titanium wears very comfortable on the wrist and true to its almost 47 mm diameter and is available in a limited edition of only 11 pieces.

Sticker Price $835,000 USD. For more info on Greubel Forsey click here.