Images Dated 5th January 2006

The sun sets over the Yenisey River near the hydroelectric power station by the town

The sun sets over the Yenisey River near Russia's second largest hydroelectric power station by the town of Divnogorsk some 40 km (25 miles) from the major Siberian city of Krasnoyarsk January 5, 2006. Due to a thermal effect of the river basin, the water does not freeze at this point for several kilometres, despite the severe Siberian frost. REUTERS/Ilya Naymushin - RP3DSFDLUOAA

Karst sandstone

Karst sandstone, known in Madagascar as tsingy, is a feature of a large ravine of ancient rock formations at Irodo, southeast of Antsiranana (Diego Suarez). The impressively sharp red pinnacles are the result of millions of years of erosion. Tsingy is a Malagasy word meaning walking on tiptoe

© Nigel Pavitt/John Warburton-Lee Photography Ltd

Seminiferous tubules

Seminiferous tubules. Light micrograph of a cross- section through seminiferous tubules in an earthworm (Lumbricus terrestris) testis. The seminiferous tubules are the site of sperm production (spermatogenesis). In the central region of each tubule are spermatozoa, formed from gametes undergoing initial meiosis and later spermiogenesis

© DR KEITH WHEELER/SCIENCE PHOTO LIBRARY