Planet Fitness takes the cake for this screen that attempts to show their numerous locations.

Planet Fitness’s unusable map featuring too many locations

The principal issue is browser performance. At this zoom level there are simply too many data points for javascript to handle. Forget dragging or zooming.

Secondly, what’s the use case for seeing all the national locations simultaneously? If it’s a matter of demonstrating convenience to a prospective member, wouldn’t it suffice to simply highlight the sum of locations? E.g. “5,000 Gyms and Growing!”