Green grass is growing all over London's landmarks--last month it was the National Theatre and this week it is Trafalgar Square. Wandering onto the green is a sweet, grassy-smelling delight, with red deck chairs, people lying down, eating lunch, reading the paper, a family playing baseball (they must have been American) and others just gawking at the sight. And not quite understanding what was going on. The answer is that the mayor, Ken Livingstone, is promoting London's "villages" and its reputation as one of the world's greener capital cities. But not that green--the sod will be gone by tonight; transferred to a park where it will be planted beneath a row of trees close to the Thames. It is all quite ecological: the 2,000 square metres of sod came from a sustainable turf farm in York and was harvested the day before yesterday with very little soil attached. A team of gardeners worked all night to lay it. Global Cool a celebrity-backed climate change group, was involved in making its journey carbon neutral. How sweet it was.