Dolphins, Seals at Home in London's Reborn River

Fifty years ago London's River Thames was so polluted that it was declared biologically dead. Now the river that flows through the heart of Europe's largest city is awash with wildlife – a triumph worth noting today, Earth Day 2005.

More than 130 seals have been spotted in the Thames since last August, according to the Zoological Society of London. Bottlenose dolphins have been seen upstream of London Bridge. And last summer the first sea horse was recorded in the Thames estuary in 30 years.

With 120 fish species, hundreds of thousands of birds, and a thriving fishing industry, the river now ranks among the cleanest metropolitan tideways in the world ... National Geographic News