Subject categories
Anthropology, Ethnology, Exploration & Travel → Rivers - Europe
Climate, Environment, Natural Resources & Disasters → Factory and trade waste - Environmental aspects
Climate, Environment, Natural Resources & Disasters → Pollution - Control equipment
Climate, Environment, Natural Resources & Disasters → Pollution - Environmental aspects
Climate, Environment, Natural Resources & Disasters → Rivers - Europe
Climate, Environment, Natural Resources & Disasters → Water - Pollution
Communications, Infrastructure, & Transport → Water - Purification
Documentary
Documentary → Documentary films - Great Britain
Mathematics, Science & Technology → Microphotography
Short films
Short films → Short films - Great Britain