Amazon, Microsoft, Google, Meta and OpenAI plan to spend at least $325 billion by the end of the year in pursuit of A.I. We explain why they’re doing it.

Rates of the disease have fallen since 1991, when a vaccine committee recommended all newborns receive the shot.

President Trump’s trip to Britain will involve horse-drawn carriages and a stay in an ancient castle. For British officials, the visit may feel less like a fairy tale.