Destination: the "green" beach towns of Uruguay

Christmas marked the start of the high season in Uruguay. That could sound like a giddy little pun on the fact that marijuana is now legal here, but it would not be in the proper spirit. In Montevideo, I quickly learn that foreigners tend to get much more excited about the landmark legislation than most Uruguayans, who kindly request that we please keep our cool.

For one thing, the new law stipulates that cannabis can never be sold to non-residents. And there are too many bongos being played in public for a visitor not to be aware that marijuana has already become common in the capital.

Possession of the drug for personal use has long been decriminalised. And, on a southern hemisphere summer evening, as I stroll from the old town to the city centre, I can smell it on the breeze and see it being smoked in the streets - not furtively, but casually, with the same urbane air of discretion and maturity with which alcohol is consumed by continental Europeans.

More striking is the ubiquity of yerba mate. Uruguay claims to have invented the grassy-tasting tea-like infusion - one of many claims contested by its neighbour Argentina - and the entire population seems openly addicted to it. Almost everyone is drinking mate from a mate (the traditional gourd of the same name) through an ornate curved metal straw called a bombilla. They drink it while walking, talking, sitting on benches in historic plazas and even while riding motorbikes, with flasks of hot water tucked under their arms as if they were oxygen tanks.

On the concourse outside City Hall, where film students are projecting their short movies on to a building across Avenida 18 de Julio, I meet a bearded young graduate called Eduardo, who has a mate in one hand and a spliff in the other. The caffeine balances out the cannabis pretty nicely, he tells me.

"But this," he says, holding up the gourd, "is much more fundamental in Uruguay."