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Why does landlocked Bolivia still have a navy?

Landlocked does not mean without navigable water. Bolivia’s naval story brings together the loss of its Pacific coast and the practical importance of inland waterways. A 2006 Library of Congress profile describes the navy’s focus on rivers and Lake Titicaca, giving the apparent contradiction a geographical explanation.

3–7 min

Questions you could explore

  • How can an institution retain a maritime identity while carrying out inland roles?
  • What work does Bolivia's navy perform on rivers and lakes as well as in its maritime traditions?

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History

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4–5 min

Calibrating the radiocarbon clock

History4–5 minCarbon-14 decays at a steady, predictable rate, which makes it look like a simple stopwatch for dating ancient wood, bone, or charcoal. However, the amount of radiocarbon in Earth's atmosphere has varied over the millennia, so an accurate date relies on calibrating the measurement against tree rings and other materials whose calendar age is already known.

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4–6 min

How do archaeologists work out what happened first?

History4–6 minA deep object is not necessarily the oldest thing at an archaeological site. A later pit can cut through earlier ground, leaving a sequence that has to be reconstructed from relationships between layers.

History

When Britain’s railways needed a shared clock

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5–7 min

When Britain’s railways needed a shared clock

History5–7 minA timetable becomes awkward when the clocks at its two ends disagree. In nineteenth-century Britain, railway journeys helped turn local time into a shared coordination problem, while the telegraph helped distribute an answer.

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