• 1 · Religion and Magic
• 2 · Nature
• 3 · Human Being, Man in General
• 4 · Society, Civilization, Culture
• 5 · Abstract Ideas and Concepts
• 6 · History
• 7 · Bible
• 8 · Literature
• 9 · Classical Mythology and Ancient History

• Top
• 2 · Nature
• 25 · earth, world as celestial body
• 25H · landscapes
• 25H1 · landscapes in the temperate zone
• 25H19 · swamps and polders

25H192 · polder, reclaimed land

• 25H1921 · pumping installation, pumping-engine (~ polder)
• 25H1922 · technical aspects and details of pumping-engine