A mechanical world timepiece having a transmission mechanism which allows the time display, such as, for example, a 12-hour hand and/or a 24-hour hand, to be directly adjusted with a turning ring having 24 time zones. The timepiece serves for the easily manageable adjustment of the time zone and the reading of the time in a different time zone. Operation could not be simpler. After a lever has been opened, the mechanism in FIG. 1 automatically engages. The gear rim (6), which is fixed with the turning ring, drives a vertical drive wheel (5), which is connected by a shaft to a clutch wheel (4). Once the pinion (4) is engaged, it drives one or two minute wheels (8, 9), which move a 12-hour wheel (10) and a 24-hour wheel (11) in a 1 h-cycle. The turning ring is thus easily turned to the desired destination at 12 h and the local time can immediately be read. Either the turning ring is now turned back to its original locality or the lever is simply closed. In the latter case, the time now continues running according to the set destination. The push-piece (2) disengages the mechanism via a rocker (3), simultaneously fixes, in the closed state, the gear rim (6) and prevents accidental adjustment of the time. The transmission mechanism can also be used for setting or changing other time displays, such as date, day of the week, month, year, minutes, or for other functions such as an alarm.