Cold economic calculation requires serious protection at Davos while the accent in Porto Alegre, Brazil, is on openness.

Events at the Brazilian social forum include a showing of images by renowned photojournalist Sebastiao Salgado.

But politics are making their mark in Brazil, too, with demonstrations in support of Iraq and, closer to home, Venezuela.

There have been attempts at a gentler kind of protest in the frost and snow of Davos...

...but with war in Iraq looming the Swiss are taking no chances and have ringed the resort with riot police.

Protesters kept away from Davos could do little but throw snowballs at police armed with water cannon.