Today is Martin Luther King Day, a US holiday which celebrates the birthday of Dr. Martin Luther King Jr - leader of the American civil rights movement, political activist and at 35 the youngest Nobel Peace Prize winner.

He was assassinated in 1968 and his remains are now held at the King Center, located just beside his childhood home. The white rectangle within a circle is Dr. King’s tomb, where there is also an eternal flame.

Probably the greatest speech of all time, Dr. King’s “I have a dream” was made to 200,000 demonstrators outside the Lincoln Memorial in Washington, D.C.

Links: The Martin Luther King Jr National Historic Site and Martin Luther King Jr (Wikipedia).

Thanks: Trina

Many thanks to reader Patrick for pointing out that the Google Earth links recently went missing from our RSS feed.

The problem is now fixed, unfortunately that means all the entries in the feed will be marked unread in your feedreader. Sorry

This is the infamous Berkeley Pit in Butte, Montana. This enormous open-pit copper mine was opened in 1955, and when it was closed in 1982, groundwater began to leak into the basin - disastrously passing through the metal deposits in the soil. The water became laden with a deadly mix of heavy metals and poisonous chemicals such as cadmium, zinc, arsenic and sulphuric acid.

There’s an estimated 30 billion gallons of water in Berkeley Pit which is (despite major cleanup efforts) still incredibly toxic. The water here was reputedly responsible for killing 342 snowgeese who landed here in 1995, and apparently has a pH level of about 2.5, which ranks it more acidic than tea, coffee, acid rain, beer, orange juice and vinegar. That’s as acidic as cola and only slightly less acidic than gastric acid… (Update: It turns out “only slightly” is misleading. See this comment for more information.)

You can read more about Berkeley Pit at WIkipedia.

Thanks to Matt, Kaley, Patia, Kari Valimaa, Jeremy, James Boorman-Padgett, Ben Hall and xramin.