All the other mountains here are tall but they're not in Africa! Kilimanjaro is one of the highest peaks in the world and considered the easiest of the seven summits (the highest peak on each contintent) to climb.

The Yangtze is one of the main rivers in China. It was controversially dammed by the Three Gorges Dam to provide hydropower.

Yep, we left off the part of the definition where it says it's a band of colors in the sky. A rainbow is typically formed when there is rain and sun at the same time, and it is always opposite the sun.

All of these can cause a wave. Water is not stable, after all, so it is easily moved around.

The Arctic Ocean is warming rapidly but it's still really cold compared to the others! Unfortunately, it is warming fast enouh that it may soon be ice-free in the summers.

Lake Baikal may not have the biggest surface area but it is the biggest by volume. This is because it is really, really deep - more than a mile!

The capital of Japan is vast. It has nearly 40 million residents in the metro area. It's also quite dense compared to other megacities and has pretty good transit!

South Sudan is brand new, though it is off to a rocky start. It separated from Sudan proper after an entire generation of civil war.

Damascus has been a settlement for more than 10,000 years. That makes it the longest continuously inhabited place on the planet.

Mawsynram, India, is really, really wet. They get more than 11,000 mm (which equals 433 inches or 36 feet) of rain there per year!

It happened in Valdivia, Chile, in 1960. It killed 1,600 people, left millions homeless and caused half a billion dollars worth of damage in 1960s money.

It is less than one half of one square kilometer. It's also entirely contained within the city of Rome.

The missing one is thermosphere.

The amount is going up by about 2-3 ppm per year. At 410, we're seeing droughts, record heatwaves and wildfires. At 1,000 there will be no ice on the planet, meaning seas will rise 270 feet. That's why the amount matters!

You cannot actually see the Great Wall without magnification. You can see all the others, which include a mine, a dump, and a complex of greenhouses!

It's at 330,000 feet and it's officially the point at which "space" begins. You can't breathe long before you get up there, but that's the officially agreed on spot. You don't want ot go over about 30,000 feet without oxygen, though, and ideally not above about 15,000.

You probably learned this as a child and it's still true. A cheetah can run up to 75mph.

This fungus is in Oregon and it covers more than 2,000 square miles! They call it the Humongous Fungus, an apt name if ever there was one.

The biggest of the big is called General Sherman. At 52,500 cubic feet, it is nearly twice the size of the next contender.

At 7,208 feet deep, this cave system is nearly a mile and a half deep! It's in the country of Georgia, in Eastern Europe. Just don't go too far down. You might awaken a Balrog!

It's a trick question! Null Island is not real, it's just a place in the sea that is at zero latitutde and longitude. Photos that have no geotag typically get tagged as being at Null Island, though, so actually there are more photos on the internet "taken at Null Island" than any other location on Earth!

Yep, there's no cloud called a Fluffismus, though we wish there were. The nice fluffy everyday ones you see are cumulus clouds.

This area is about 1,200 feet below sea level. The Dead Sea is slowly evaporating and may eventually disappear altogether as there is no water source to feed it.

Waves can look rounded but this is not a category of wave. There is, however, such a thing as a tubular wave, which is a beautiful wave with a rounded tunnel of air inside!

Wind always moves from higher to lower pressure areas. A doldrum, where there is no wind, means the air pressure in that area is very steady.

The Amazon rainforest is 2.1 million square miles, which is 1.3 billion acres. An effort is being made to protect it, as only 2/3 of it is currently still standing.

This settlement was nearly destroyed when a freeway was built through the site. It appears to date back to 7500 BC.

The Atacama is the driest place on Earth. It gets so little rain that Lake Vanda, in the same region, is three times saltier than the ocean.

Beaches, headlands, and tombolos are all features of coasts. A tombolo is a sandbar that joins an island to the mainland.

These amazing-looking hills are not made of chocolate, alas. They just turn brown in the dry season. They're conical "haycock" hills that are likely to become a UNESCO protected site.

Undertow is not a type of plate boundary. Plates do sometimes go under one another, but that is called subduction.

Erupting is a subcategory of "active." If a volcano is active, it may just be giving off gas, but it may also be erupting. Otherwise, it is extinct (dead forever) or dormant (might go off, but not currently).

At 19,715 feet, the Yarlung Zangbo canyon in Tibet is by far the deepest. It is nearly four miles deep in places.

It's literally that simple: trees are taller. They also typically have a single trunk of at least 2 inches in diameter and a height of 4.5 feet. Shrubs have multiple, shorter woody "trunks."

These amazing stationary clouds form in the high troposphere and are sculpted smooth by gentle air currents. They are quite rare and very beautiful.