Our picks for the week of April 18-24:
• Happy Birthday, Earth Day! Our animated tribute celebrates 40 years.
• That may look like a regular kitty (above,) but it's not. Here are 11 hybrid animals that will make you do a doubletake.
• Iceland's volcanoes remained in the headlines all week (and produced a series of stunning images, including the one at left). But here's an angle you might not have considered: the air travel disruptions stranded produce, forcing residents of northern Europe to eat local vegetables instead of their exotic brethren.
• Water supplies in the United States are safer than they used to be, but plenty of old and new dangers still lurk beneath the surface. Learn more about your drinking water with this enlightening Translating Uncle Sam piece.
• A guest columnist says the founder of Earth Day would be disappointed that today's environmental leaders have failed to address overpopulation.
• The Sierra Club is working with universities to kick coal off campus. Find out what they've accomplished so far.
• Lights, camera ... recycle! That's the new catchphrase as NBC's 30 Rockefeller Center goes green.