The 10 most important things in the world right now

Reuters/Kazbek Basayev

A woman runs along an embankment at the Olympic park in the Black Sea resort of Sochi, Russia.

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

1. 2016 got off to a horrible start in the European markets, with every single major bourse closing in the red on the year's first day of trading. Terrible data from China sent all of Europe's major stock indices plunging early on Monday morning

2. Barack Obama is moving ahead on plans to require background checks for guns purchased from dealers even if they're bought online or at gun shows. The White House is rolling out a series of long-awaited executive steps aimed at curbing gun violence.

3. China's six-month-old campaign to calm share markets will be put to the test when stocks reopen on Tuesday, a day after selling triggered an unprecedented trading halt and risked undermining state rescue efforts estimated to have cost around $140 billion.

4. Britain should take in 3,000 refugee children who are traveling through Europe alone and are at risk of falling prey to human traffickers, a parliamentary committee said on Tuesday.

5. Saudi Arabia's growing international isolation and Iran's rising regional influence have led the kingdom to "double down" on protecting its interests, according to a new analysis of the world's top 2016 risks by Eurasia Group, the world's largest political-risk consultancy.

6. Facebook has a contingency plan in case the company falls out with Google, according to The Information. According to the report, Facebook has developed a way to deliver app updates without going through the Google Play Store.

7. A fact-finding mission of the global anti-chemical weapons watchdog has found indications that some people in Syria were exposed to deadly sarin gas, or a compound like it, according to a United Nations report.

8. The office building in San Bernardino, California, where 14 people were massacred last month by a married couple inspired by Islamist militants, has reopened.

9. Geopolitical experts estimate that the terrorist group ISIS will remain an "unfixable" problem in the coming year. Multiple nations are carrying out air strikes against the terrorist group in both Syria and Iraq, including Britain and the US.

10. Facebook CEO Mark Zuckerberg is adding a physical challenge to his 2016 to-do list: running a mile a day for the whole year. Zuckerberg announced his goal of running 365 miles this year on his Facebook page.

And finally ... Vladimir Putin once joked at a lavish banquet that he was capable of destroying the US in 30 minutes or less.