The Breguet Marine Hora Mundi (Reference 3700) is a highly revered luxury travel timepiece introduced in the late 1990s as a sporty yet elegant interpretation of a traditional dress watch. Featuring an advanced world-time complication packed into a slim profile, it is celebrated by collectors as one of the smartest and most visually balanced travel watches ever made.

The Hora Mundi 3700 relies on an ingenious dual-crown system that avoids cluttered pushers on the side of the gold case. 

• World Time Tracking: The primary crown controls the main hour and minute hands to display local time. 

• The Cities Ring: An inner crown allows the wearer to rotate the external city disk. As you change your city focus, the 24-hour day/night ring seamlessly indicates whether it is daytime (top half) or nighttime (bottom half) in that zone. 

• Synchronized Date: Positioned cleanly at the 12 o'clock position (or 6 o'clock depending on regional iterations). Unlike common dual-time watches, when you manually cycle through time zones, the date wheel automatically clicks forward or backward in perfect synchronization with the hour changes.

• Case Size: 38mm diameter, 8.7mm thickness, and a 45.5mm lug-to-lug distance, allowing it to easily slip under a tight dress sleeve. 

• Case Material: Solid 18k Yellow Gold (Ref. 3700BA) or 18k White Gold (Ref. 3700BB), featuring Breguet's signature coin-edge fluted case band. 

• Movement: Breguet Caliber 563 automatic movement (derived from the premium Lemania 8810 base) with 25 jewels. 

• Dial Architecture: Solid silver two-tone dial with a hand-guilloché central pattern, a brushed Roman numeral hour ring, a 24-hour day/night track, and an outer ring listing 24 major global cities. 

• Hands: Signature blued-steel open-tipped Breguet hands. 

• Water Resistance: 30 meters.