Dancing robot and driving simulator on show at Lisbon's Web Summit

Global tech leaders packed Lisbon's annual Web Summit Tuesday to talk artificial intelligence, robots and startups -- all under the shadow of global tensions over cutting-edge hardware and software and the resources needed to build them.

Visitors explored bright blue-and-pink stands under a grey November sky, on the lookout for the latest in quantum computing or humanoid robots. Over four days, the "Davos for geeks" is set to welcome over 70,000 visitors from 150 countries, including 2,500 startups and 1,000 investors, according to organisers.