It's Crisis at a Glance! The Federal and the central banks of all nations, basically have one mission - to keep economies sound and stable - as much as possible - by encouraging borrowing to fight recession, and dampening down borrowing to fight inflation.
Ever since the Great Recession, and whatever analogous travails other countries went through, there has been such anemic growth that renewed recession has been a greater concern than inflation.
So the Fed and other central banks have been pushing their own interest rates ever low. In December the Fed did a tiny rate *hike* for the first time in seven years.
But other central banks are still pushing lower to stimulate their economies. The Dutch, the Danes, the Swiss and now the Bank of Japan have gone to "negative" interest rates.
Central banks can actually pay private sector banks to take money and lend it out.
This stuff is working - the post-recession growth cycle has been long, and looks like it will run longer still.