What advantages do highly sophisticated racing machines give the cycling pros? To find out, we pit a Guardian journalist on a £6,000 Tour de France bicycle against elite national-level rider Iain Cook on a variety of less advanced machines, including a Dutch shopping bike and a London hire bike. Who will win? Peter Walker reports from Herne Hill Velodrome in south London
The visibility of distilled water is about 80 metres. Blue Lake, on New Zealand’s South Island, clocks in at 76 metres. Here are the first-ever photos of this newly discovered natural wonder, taken by Klaus Thymann of Project Pressure and supported by New Zealand Department of Conservation and New Zealand Tourism.
Nipped fingers and handfuls of guano will be the order of the day for wildlife rangers on the Farne Islands as they embark on an epic census on Friday to discover whether puffin numbers have plummeted after a year of extreme weather.