What did the world most care about in 2015? Google News Lab looked at trillions -- that's right trillions -- of queries across Google search, Google News and YouTube to find out.
Here's a look at the top 30 news subjects the world wanted to know about this year. One hint -- the number one topic received nearly 900 million searches and far outpaced number two.
No. 30: 10 million searches +
Water on Mars apparently fascinated the world more than close-up photos of little Pluto. Perhaps it was because the discovery, announced in September, stirred the imagination regarding the potential for life beyond planet Earth and the desire to travel to the Red Planet.
Most popular questions: "How long does it take to get to Mars?" and "How far is Mars from Earth?"
Arizonans were the most interested in Mars among the residents of our 50 states.
By CBSNews.com Senior Photo Editor Radhika Chalasani