P-waves, or Primary waves, are longitudinal compression waves. They travel faster than other seismic waves and can move through solids, liquids, and gases.

China has the greatest elevation span, ranging from Mount Everest (8,848m) to the Ayding Lake (-154m), a difference of over 9,000 meters.

Angel Falls has the greatest single uninterrupted vertical drop of 807 meters.

The Maldives is the flattest country on Earth. Its highest natural point is only about 2.4 meters (approx 8 feet) above sea level.

Mawsynram, a village in the East Khasi Hills district of Meghalaya state in northeastern India, holds the record for the highest average annual rainfall.

Australia is the lowest and flattest continent, with an average elevation of only 330 meters. Note: Antarctica is the highest continent by average elevation.

The Panama Canal underwent a major expansion project completed in 2016, adding a third lane of locks to accommodate larger vessels.

On the surface of a sphere (like Earth), the shortest path between two points is an arc of a Great Circle, often used in aviation navigation.

While the Arctic is famous for rapid warming, Antarctica, particularly the Antarctic Peninsula, and Asia are experiencing some of the most rapid and consequential warming trends, though the official title of 'fastest' often goes to the Arctic or, recently, Europe.

Driven by rising life expectancy and declining birth rates, the **65 and over age group** is the fastest-growing demographic segment in many countries, leading to challenges in healthcare and pension systems.