The Swiss Moonphase Watch
Many mechanical watches do more than just tell time. They have complications that may include the display of the date, the use of a stopwatch, an automatic winding mechanism, and an alarm. Some might even dabble in astronomy with moon phases.
These are the shapes of moon that we see at night because of the way that the sun hits it on that particular day. The changes are subtle and repeat periodically. Familiarity of the phases can give certain individuals an advantage in their activities.
For example, the full moon is important for many maritime species. It is during this time that they mate or spawn. Fishermen and scientists can use this information to time their hunts and studies. The moon also affects honeybees, iguanas, and more.
Lots of theories abound regarding lunar effects on human behaviour but these are still being debated. Meanwhile, you can observe for yourself with a Swiss moonphase watch.