The annual World Economic Forum got underway in Davos on Tuesday, with US President Donald Trump giving a keynote speech in typically boisterous style as business leaders grappled with balancing their profits against the menace of climate change.
Here are five highlights from the first day of the 50th edition of the glitzy meeting at the Swiss resort.
As Swedish teen climate activist Greta Thunberg warned participants at the summit that they were not even trying to fight climate change, Trump resorted to apocalyptic language to describe those who do not share his skepticism on global warming.
People saying that the world is in the throes of an environmental crisis are the "perennial prophets of doom", "the heirs of yesterday's foolish fortune tellers" and not to mention "radical socialists", said the US leader.
Having sat quietly through his speech among the audience, Thunberg was unrepentant in later remarks. "Our house is still on fire," she said.
The plumber who came in from the cold
There is a relatively low-key Russian presence at Davos this year as Russia's economy still suffers due to the isolation following the 2014 annexation of Crimea.
But according to a Swiss newspaper report, a group of Russians had been active in Davos months before the World Economic Forum had even began.
Tages-Anzeiger said Swiss police in August discovered two suspected Russian agents in Davos, including one who claimed to be a plumber. The paper said the men may have been preparing a wiretapping or hacking operation in Davos.
They were stopped, but not arrested.
Some way off gender parity?
The WEF is keen to make clear that it is working hard to improve the gender balance on its panels, still heavily skewed towards men.
But there were red faces when the moderator muddled the names of the women on one panel, managing to call both of them Vicky.
"Strange, uh, two women on a panel?" said Rachel Kyte, Special Representative of the UN Secretary-General for Sustainable Energy for All, after the moderator called her Vicky, the name of the other woman on the panel, Vicky Hollub, the CEO of Occidental Petroleum.
This year 24 percent of the participants are women, according to the organizers.
Saving the planet, step by step
The big Davos buzzword this year is sustainability, with organizers keen to show that the event leaves a minimal environmental footprint.
Posters boast that the painting for the signs is made from seaweed rather than chemicals and the carpets are made from recycled fishing nets.
But other innovations are less daring. Shoe grips for Davos' icy streets and and even walking maps are handed out in a bid to encourage participants to get about on foot, rather than make short journeys in the cars that make the gridlocked streets of the village feel like an urban rush hour during the forum.
Hacked off humans
As if worrying about the future of the planet -- or being told by Trump that to worry was doom-mongering -- was not enough, Israeli author and historian Yuval Noah Harari had a potentially even more troubling message.
Soon, he told worried participants at a panel meeting, artificial intelligence would be possible to hack into humans just as today computers and bank accounts are hacked into.
"If you have enough data about me, enough computing power and biological knowledge, you can hack my body, my brain, my life," said the author of the bestselling book "Sapiens".
"You can reach a point where you know me better than I know myself," he said, adding that once that point is passed "we have no idea what happens" with all political systems.