The 10 most important things in the world right now

Reuters/Eric Gaillard

A man swims in the Mediterranean Sea during a warm and sunny winter day in Nice, France March 1, 2016.

Good morning! Here's what you need to know on Wednesday.

1. Hillary Clinton and Donald Trump had strong results on Super Tuesday - the biggest night so far in the 2016 presidential primary campaigns. Both candidates won several primary and caucus contests.

2. FBI Director James Comey admitted that a "mistake was made" with the San Bernardino investigation during a surprisingly contentious hearing held by the US Congress on Tuesday. Comey and the FBI are seeking to force Apple to build custom software to access encrypted data on a terrorist's iPhone.

3. The dispute around London's long-awaited Night Tube service seems to be nearing an end after members of one of the largest Tube unions involved in the pay and work conditions row backed an offer from London Underground (LU) bosses.

4. Ratings agency Moody's has placed China's sovereign rating on watch negative, suggesting a one-in-three chance that the group may downgrade the nation's Aa3 rating in the months ahead.

5. Tidal, the music streaming service owned by rapper Jay Z and a collection of other celebrities, has fired its CFO and COO. Chris Hart was reportedly fired over a dispute about how the company handles user and streaming numbers, according to Swedish news site Breakit.

6. Powa Technologies, the London-based payment company that fell into administration late last month, fired around 5% of its staff on New Year's Eve, causing disruption and delays to a project it had just raised $80 million (£57.2 million) for.

7. Osama bin Laden wrote a letter calling on the American people to help President Barack Obama fight "catastrophic" climate change and "save humanity", in the latest evidence of his worries about environmental issues, newly released documents show.

8. A Turkish hacker who US prosecutors say masterminded a series of cyber attacks that enabled $55 million to be siphoned from automated teller machines around the world pleaded guilty on Tuesday. Ercan Findikoglu, 34, pleaded guilty in federal court in Brooklyn, New York, to five counts

9. The Rolling Stones have officially announced that they will be performing a free concert in Havana, Cuba, on March 25. It is the first time the group will be performing in the country.

10. A new poll shows that the campaign for Britain to pull out of the EU is currently in the lead - but only just. The research, put together by Future Thinking, says 33% of respondents plan to vote to leave the 28-member union on June 23, compared to 32% who want Britain to remain.

And finally ... The 20 most expensive cities to live and work in.