What is the number 1 YouTube video ever?

Can you tell me, what exactly is the most popular video on YouTube, as measured by views and engagement? I'm curious to know what kind of content has captivated the hearts and minds of viewers worldwide, to the extent that it has reached the pinnacle of popularity on the world's largest video-sharing platform. Is it a music video, a comedy sketch, a viral challenge, or perhaps something entirely unexpected? I'm eager to learn the answer to this intriguing question.