The chief greenhouse gas was measured Thursday at 400 parts per million in Hawaii, a monitoring site that sets the world's benchmark.

NPR: Experts: CO2 Record Illustrates 'Scary' Trend

Its other monitoring site, in Armonk, N.

WSJ: Sniff, Sneeze, Blow, Wipe, Repeat

The site opened in 1941 and played a key role in monitoring Britain's skies during World War II and Cold War.

BBC: Ex-RAF radar base in Norfolk up for sale on eBay

The site, opened in 1941, was used as a radar monitoring station until 2005, before being sold to developers.

BBC: Former RAF Neatishead base sold for ?2.5m in eBay auction

The chicane is supposed to allow only buses to pass, but monitoring by police over a week in April revealed 822 vehicles drove through the site.

BBC: Northampton rat-run 'car trap' ignored by drivers

SnapNames is offering domain name monitoring services targeted toward large corporations, Web site design shops and law firms specializing in intellectual property practices.

CNN: New service back-orders domain names