LONDON (AP) — 2015 ends with the global economy at a juncture and markets a bit edgy.

The main engines of the global economy are not in sync and the markets know it. That's evident from the regular bouts of unease that gripped investors over the past 12 months.

Worries over China's economic slowdown were more often than not the cause of those jitters. Although China is still posting growth that developed economies are unlikely to ever see again, its policymakers know there are challenges ahead.

Not least is transforming an economy that's been reliant on trade with the rest of the world into one that depends more on spending by its growing middle class. That challenge sparked deep fears in August, when global stock markets suffered some of their biggest declines since the bad days of 2008.

The repercussions of China's slowdown have been felt far and wide, particularly in the energy and commodity markets, where prices have fallen. Commuters around the world have enjoyed the benefits of cheaper gas, but central bankers, notably in Europe, are worried that may lead to a debilitating period of falling prices that can cause stagnation.

Despite the turmoil, 2015 appears to be ending on a calm note, mainly thanks to the strength of the U.S. economy. It's so healthy the Federal Reserve finally decided — after much agonizing —to start reversing the super-low interest rate policy it put in place during the global financial crisis. On Dec. 16, the Fed raised interest rates for the first time since the summer of 2006.

It's not just the big economies that cause jitters.

Greece, a country of barely 11 million, captured nearly as many headlines as China and the U.S. this year as the country teetered on the brink of bankruptcy and an exit from the euro, Europe's single currency.

And speaking of surprises, who would have thought that Volkswagen, a pillar of German engineering and reliability, would be embroiled in a cheating scandal that's undermined its venerable brand?

As these and other major stories broke, Associated Press photographers were there to capture some of the most memorable moments of 2015 for the world of business.