1) The development of blockchain technology, first introduced in 2008 with the creation of Bitcoin, has enabled secure and decentralized digital transactions and led to the emergence of cryptocurrencies.

2) 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.

3) The croissant, a flaky and buttery pastry, is an iconic French delicacy. It is made by layering dough with butter, rolling and folding it multiple times to create a laminated structure. The croissant can be enjoyed plain or filled with various ingredients, such as chocolate, almond paste, or ham and cheese. It has become popular worldwide and is a staple in breakfast menus and bakeries, symbolizing French culinary expertise and savoir-faire.

4) The #MeToo movement, originating in 2006 and gaining widespread attention in 2017, raised awareness about sexual harassment and assault, encouraging survivors to share their experiences and promoting discussions on consent and gender equality.