Rolex has been around for over a century and has been coined in making “the only watch that matters.” Providing reliable and durable timepieces, Rolex is probably the most eminent luxury watch brand in the world.

We’ve rounded up a few little known facts about this iconic company.

1. All of Rolex’s watches are handmade. 
It takes about a year to make one Rolex watch. Every watch is painstakingly made by hand in Switzerland. Rolex watches are given all the attention and dedication to ensure they meet the coveted brand’s strict standards. Virtually everything is made from base materials in-house. Once all the parts for a Rolex watch are completed, they are then mostly hand-assembled and independently tested. The quality assurance process is rather intense.

2. Every single Rolex is pressure-tested before leaving the plant. 
Being at the forefront of water resistant technology involves a multitude of steps. Every Rolex is placed in a sensitive air-pressure chamber to determine if there are any air leaks in the case. If a medical-grade optical sensor finds any condensation or water infiltration, the watch is scrapped.

3. Rolex uses the most expensive stainless steel in the world, also known as 904L. 

Other high-end brands use a stainless steel grade (known as 316L) in their designs, but 904L is exclusive to Rolex. The steel is much more expensive, and said to be resistant to rust, corrosion, and pitting — a real problem for salt water divers.

4. The most expensive Rolex sold for $17.75 million. 
Known for its Hollywood pedigree, the 1968 Reference 6239 Daytona, made from stainless steel and leather, is one of the most iconic Rolex models. It sold for nearly $18 Million at the October 2017 at Phillips’ inaugural watch auction in New York City.

5. An in-house foundry makes all the gold for Rolex watches. 
Rolex makes their own gold. Because they control the production and machining of their gold, they are able to strictly ensure not only quality, but look of these extraordinary materials. Rolex is the only watchmaker that makes their own gold or even has a real foundry in-house.

6. Rolex Headquarters outshines any high level security prison. 
Rolex holds bars of Everose gold worth $1,000,000, so you can’t blame them for having employee fingerprint scanners, bank vault doors, iris scanners, and unmarked armored trucks to move Rolex parts from location to location.

7. Nobody knows what Rolex actually means. 
Watchmakers assume the name comes from the French term horlogerie exquise, meaning exquisite clockwork. But Rolex founder Hans Wilsdorf admitted the name Rolex was picked because he wanted a word that was short and looked good on a watch face, and could be pronounced in any language. He also thought that the name sounded like the noise a watch made when it was being wound.

8. Rolex might be a luxury Swiss company, but it originated in London. 
The company started out assembling watches, not making them. Two brothers-in-law, Hans Wilsdorf and Alfred Davis started out as “Wilsdorf and Davis,” putting movements into cases for jewelers. They later relocated the brand to Geneva, Switzerland in 1919 due to wartime taxes levied on luxury imports.

9. On their Roman numeral dials, Rolex still use IIII rather than IV.  
IIII is known as the “Watchmaker’s four,” and is a matter of aesthetics and visual symmetrical balance.

10. Rolex watches have gone to the deepest point of the ocean. 
When James Cameron descended into the Mariana Trench in 2012, he sported a Rolex Deepsea Challenge, which was guaranteed waterproof to a depth of 12,000 meters (39,370 feet). The watch kept perfect time throughout the 7 hour underwater journey.