1) Celtic mythology encompasses the folklore and legends of the Celtic peoples across Europe, particularly in regions like Ireland, Scotland, and Wales. It features deities like Morrigan, Cernunnos, and Brigid, and delves into themes of nature, magic, and the heroic exploits of legendary figures like Cu Chulainn.

2) The concept of augmented reality (AR) involves overlaying digital information and virtual objects onto the real world, enhancing the user's perception and interaction with the environment.

3) Emma Stone is an American actress known for her roles in films such as "La La Land," "Easy A," and "The Help." She has received critical acclaim and several awards, including an Academy Award, for her performances, establishing herself as a talented and versatile actress.

4) The ocean covers about 71% of the Earth's surface and contains roughly 97% of the planet's water.