To celebrate the earth day on Saturday, April 22nd, in addition to Apple retail store employees to wear a green T-shirt, Apple has also brought an earth day challenge for Apple Watch users. The challenge encourages Apple Watch users to go outdoors, complete 30 minutes of outdoor sports, unlock new iMessage stickers and special achievement awards.
Earth Day challenge: to celebrate the earth day in April 22nd. The user can be 30 minutes or more walking, running, cycling or swimming, wheelchair exercise and other activities, through the Workout application or other third party applications to collect health data is transferred to the application, the user can obtain special stickers for use in iMessage.
Prior to this, Apple has been celebrating Thanksgiving and the arrival of the new year around the world held a similar exercise challenge. These are the stickers that will be unlocked when Earth Day challenge is completed: