• Biology
• Other Natural sciences
• Travel

Biology

• Tree of Life project
• Mammals of the World
• Birds of the World
• Birding around the World (good collection of trip reports, of interest to all naturalists)
• Mammal Watching
• Surfbirds.com (World birding news)
• Reptile Database (Reptiles of the World)
• Amphibians of the World
• Fishbase (Fishes of the World)
• Gymnosperms of the World
• Biospeleology
• Bat Conservation International
• Species database of Chinese fauna
• Virology
• Arachnology Web
• Wonderful Word of Rotifers
• Fungiphoto.com (best viewed while high on Psylocibe)
• carnivoreconservation.org (worldwide news on carnivores and other mammals)
• Crocodopolis (Crocodiles of the World)

Other Natural sciences

• Science News Daily
• Online Meteorology Guide
• Storm Track (info on tornadoes and meteorology in general)
• Current volcanic eruptions from USGS
• General volcanology information (MTU)
• Sky and Telescope (astronomy news)
• Cool astronomic pictures daily
• Space Weather Bureau (meteor showers, Solar flares, auroras etc.)
• Hourly auroral activity reports
• Atmospheric optics (Halos and other phenomena - lots of beautiful photos)
• Conversion to Universal Time
• Caves of the World
• World Glaciers Inventory

Travel

• World's weather in one picture
• Languages of the World
• Alternative Dictionaries (what to say if you are called kus umak in Iraq or cabron in Peru).
• Academy of Free Travel (hitchhiking in Russia and elsewhere, mostly in Russian)
• Russian backpacker's forum, also mostly in Russian
• UNESCO World Heritage List
• Tide tables worldwide
• Mexican auto insurance online
• Pamir travel guide
• Mexico Desconocido online
• Madagascar for naturalists
• Japan guide
• Kuril Islands network