A weather front rolls in from the horizon, storm clouds darken the sky, and (at least 1.3 billion times a year) lightning strikes. Last month, the National Weather Service promoted their Lightning Safety Week, with information designed to call attention to safe practices, helping people avoid lightning strikes which kill an average of 100 people every year. While the exact nature of the initial formation of lightning remains a subject of debate, what is known is that lightning strikes are caused by electrical imbalances present in the clouds. Those imbalances correct themselves suddenly, with an often spectacular light show - which I've tried to show here, with a handful of recent photographs of lightning from around the world. (26 photos total)

The 96th Tour de France cycling race is currently underway, with the final, 21st stage of the 3,445 km (2,141 mi) race coming up on Sunday, July 26th. At this time, Alberto Contado of Kazakh team Astana appears to be headed toward a second tour title, currently leading riders Andy Schleck of Team Saxo Bank and Luxembourg and, in 3rd place, Lance Armstrong, also of team Astana. Armstrong's recent emergence from retirement to return to this year's tour has been the focus of much of this year's media coverage. 180 riders in twenty teams started in Monaco on July 4th, heading for the final ride into Paris this weekend. Collected here are a handful of images from the 2009 race. (40 photos total)

"An adrenaline junkie has taken in-line skating to new heights and set a new world record after racing down a roller coaster at speeds of 56mph.

Dirk Auer decided to go where no sane man or woman had gone before and skated down an 860 metre track in just over a minute.
Wearing specially designed in-line skates, the German made the attempt on the Mammoth roller coaster at the Trips Drill theme park in Stuttgart...

"The roller caster is wooden and so unlike rides made from iron and steel there was always a chance of the odd nail or screw that would not be entirely flat.

If the skates were to catch a stray nail then I could have fallen and I would almost certainly have died. " 36-year-old Dirk Auer said.

Let's say you're a spy, out in the field, spying. You need instructions now and then from headquarters, but you don't want to risk exposure by picking up a phone (tappable) or getting an e-mail (traceable). Face-to-face meetings carry their own risks. What do you do?

One solution, dreamed up during the Cold War: Listen on shortwave radio at a predetermined time and frequency for a message that only you can understand. Numbers stations, it turns out, are the one-way chatter of espionage agencies to their spies. This isn't conspiracy theory hokum; it's referenced in a dozen-plus memoirs of assorted ex-spooks and defectors. And though numbers broadcasts might sound low-tech in the age of the BlackBerry, the idea isn't utterly cockamamie.

"Even if you assume that most of the messages are 'pick up this money' or 'drop off the laundry,' think about what numbers stations represent. The only way a secret like this can be kept is if you live in a society where everybody is obeying and everybody is a little sleepy. But if you're a curious kind of chap you'll wonder, if your government can keep this a secret, what other secrets are they keeping."