A straight line down
What's Underneath You?
Set where you're standing, then scroll straight down \u2014 through soil, bedrock, the mantle, the core, and out the other side of the Earth. (Spoiler: it's probably ocean.)
Where are you standing?
\u2014 or pick a city \u2014
\u2193 Now scroll. Mind the heat.
12,742 km later \u2014 the other side
The far surface
Set your location to find out where you'd surface.
About This Toy
What's Underneath You answers a question every kid asks and most adults never resolve: if you dug straight down and didn't stop, where would you end up? You set your spot on the planet and fall \u2014 through the thin skin of soil and rock we live on, into a mantle thousands of kilometres deep, past a core hotter than you can picture, and back up the far side to the one point on Earth exactly opposite you.
Two things tend to surprise people. The first is how absurdly thin the crust is: everything you have ever built or walked on sits in the top half of one percent of the trip. The second is where you come out. Because most land sits opposite ocean, the overwhelming odds are that your straight-down tunnel surfaces in open water \u2014 for almost all of North America and Europe, somewhere in the Indian Ocean or the empty southern Pacific. You will fall through the most extreme environment in the solar system and arrive, anticlimactically, at some waves.
How It Works
- Set your location \u2014 tap "use my location", pick a city, or it's fine to just explore from a default.
- Scroll down. The readout up top tracks how far you've fallen, the temperature climbing around you, and which layer you're passing through.
- At the halfway mark you cross the center of the Earth \u2014 6,371 km down, the deepest point there is \u2014 and start rising up the far side.
- Arrive at your antipode, and find out whether the universe gave you dry land or, far more likely, the sea.
Why This Exists
We spend our whole lives on a surface we treat as the whole world, when it is really the lid of something vast and violent we almost never think about. Under every quiet street is a furnace the size of a planet, churning liquid metal and generating the magnetic field that keeps the atmosphere from being stripped away. What's Underneath You is a way to feel that, briefly \u2014 to trade the flat map for the terrifying vertical one.
And the antipode at the end is its own small lesson in scale and loneliness. The "other side of the world" turns out, for most of us, to be nowhere at all \u2014 a patch of open ocean no one will ever visit, sitting in perfect opposition to your kitchen. It is strangely comforting. Straight down from you, right now, is the middle of the sea.
Frequently Asked Questions
What is What's Underneath You?
A free scrolling toy. You set your location and travel straight down through every layer of the planet \u2014 soil, bedrock, mantle, outer core, inner core \u2014 and out the far side, to the exact point on Earth's surface opposite you.
Where does the journey come out?
At your antipode: the point directly through the center of the Earth from where you stand. For most people it lands in open ocean \u2014 if you're in the United States or Europe, you'll surface somewhere in the Indian or southern Pacific Ocean.
Are the depths and temperatures real?
Yes. The layer depths, temperatures, and pressures are real, drawn from standard geophysics: about 35 km of crust, a mantle down to 2,890 km, and a center around 6,000\u00b0C \u2014 as hot as the surface of the Sun.
How does it know my location?
Either you tap use my location and your browser asks permission and never sends it anywhere, or you pick a city, or you type coordinates. Everything runs offline in your browser, including the land-or-ocean check at the other end.
Do I need to install anything?
No. What's Underneath You runs entirely in your browser. There is no download, no signup, and no account. Set your spot and start scrolling.
Does it work on mobile?
Yes. It works on any modern mobile browser, including Chrome, Safari, and Firefox. Scrolling is the only control.
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