by Claudine Zap We have reached the 50-day mark of the oil spill in the Gulf of Mexico . As the oil slick continues to spread, it's almost impossible to take our eyes off the worst environmental disaster in U.S. history. Eyewitnesses are capturing the grim mood on the ground â€" and in the water. Oil covered birds, a National Guardsman suited up for cleanup, and the globs of oils that have washed up on the beach all get their closeup in this Flickr slideshow .