1) 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.

2) The assassination of Archduke Franz Ferdinand of Austria in 1914 triggered the start of World War I.

3) Pizza, a popular Italian dish, originated in Naples and is now enjoyed worldwide. Traditional Neapolitan pizza features a thin, chewy crust topped with San Marzano tomatoes, mozzarella cheese, and fresh basil, cooked in a wood-fired oven. It has become a global culinary icon, with countless regional and international variations, making it one of the most beloved and versatile foods globally.

4) 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.