NASA's Cassini Spacecraft is now reaching the end of its four-year prime mission (on June 30th), and about to enter into its extended mission. What a nice excuse for a retrospective of some of the great images sent back home by Cassini over the past four years. (12 photos total)

Members of an unknown Amazon Basin tribe and their dwellings are seen during a flight over the Brazilian state of Acre along the border with Peru in these May, 2008 photos distributed by Survival International. Survival International estimates that there are over 100 uncontacted tribes worldwide, and says that uncontacted tribes in the region are under increasing threat from illegal logging over the border in Peru. (7 photos total)

After nearly 70,000 confirmed deaths and five million people left homeless (as of May 29th), the Sichuan Earthquake of 2008 continues to cause hardship across the region. More than 30 "quake Lakes", formed by landslides have flooded many areas, relief and supplies are still needed and the cleanup continues. (13 photos total)

Beichuan Qiang County, in Sichuan, China was one of the worst-affected regions during the Great Sichuan Earthquake of May 12, 2008. The townships of Qushan and Leigu were hit particularly hard, concrete structures crumbling to rubble under their own weight, or being crushed by landslides. (10 photos total)

Indigenous natives from several tribes near Brazil's Xingu River attended and protested a gathering set up to debate the impact of a proposed hydroelectric dam. Mobs of Indians surrounded Brazilian Eletrobras engineer Paulo Fernando Rezende minutes after he gave a presentation. Rezende emerged shirtless, with a deep, bloody gash on his shoulder, but said "I'm OK, I'm OK," as colleagues rushed him to a car.

It was not immediately clear whether Rezende was intentionally slashed or received the cut inadvertently when he was surrounded and pushed to the floor. Police said they were still investigating and no one was in custody.

Tensions were running high at the meeting, where about 1,000 Amazon Indians met with activists to protest the proposed dam on the Xingu River. Environmentalists warn it could destroy the traditional fishing grounds of Indians living nearby and displace as many as 15,000 people. (12 photos total)