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Explore the forms of Earth’s surface and how they develop.
Landforms · Map guides
The Sargasso Sea is an open-ocean region within the North Atlantic subtropical gyre, defined by circulating currents rather than an enclosing coastline. It is named for floating Sargassum…
Lake Salda · Geology · Map guides
Lake Salda is a closed-basin, alkaline lake in Burdur Province, southwestern Türkiye, known for its white mineral shoreline. Its magnesium-rich waters support unusual carbonate deposits associated with microbial…
Landforms · Explainers
Quick answerA river terrace is a step-like remnant of an older river valley floor, left above the active channel after the river cuts to a lower level. Its…
Landforms · Explainers
Quick answerAn alluvial fan is a spreading accumulation of sediment where a stream or sediment-rich flow leaves a confined valley and deposits material on more open ground. Its…
Ebro River · Landforms · Map guides
The Ebro begins close to Spain’s northern coast but does not take the short route to the Bay of Biscay. Its course leads inland and southeast to the…
Lisbon · Landforms · Map guides
The river beside Lisbon has already crossed a large part of Spain before it reaches Portugal. Its changing name can hide that continuity: the Spanish Tajo, Portuguese Tejo…
Portugal · Borders · Map guides
One river from Spain to the AtlanticThe Douro and Duero are the same river: Douro is its Portuguese name and Duero its Spanish name. It rises in Spain,…
Kathmandu · Cities & capitals · Map guides
Kathmandu is a Himalayan capital, but the streets at its center do not sit on a snowy summit. The city occupies a much gentler surface inside a mountain-ringed…
Niger River · Countries & regions · Map guides
The Niger River’s route is easy to misread: it starts in Guinea, curves far into the West African interior, and reaches the Atlantic in Nigeria. Along the way,…
Volga River · Lakes · Map guides
Where does the Volga River flow?The Volga flows through European Russia from the Valdai Hills to the Caspian Sea. About 2,193 miles (3,530 kilometers) long, it is Europe's…
Landforms · Explainers
The Baltic is a sea, but its water is much less salty than ordinary open-ocean water. The explanation lies in its water budget and its narrow connections to…
Countries & regions · Map guides
Lake Victoria looks like a single blue shape on a map, but its geography involves three different scales: the lake shared by three countries, the larger catchment reaching…