For Kids · The land and the sky · The ground under you

The ground under Brussels

Brussels-Capital · Atlantic Europe

Fall · October 7, 2026

Brussels, Brussels-Capital

Try it

Dig down under Brussels

Drag the spade down, or tap Dig deeper, through the leaves, the living topsoil and the subsoil, all the way to the bedrock that is really down there.

About 0 cm down

The grass

the top of the ground

Under the grass is a whole hidden world. Drag the spade down — or press Dig deeper — to find out what is down there.

Layer 0 of 5

It takes hundreds of years to make one centimetre of topsoil. The depths are typical — every place is different — and the ruler is squashed at the bottom so the rock fits on the screen.

Say it like this

Age 2“Dig, dig, dig! Who lives down there? A wiggly worm!”
Age 4“Leaves, dark soil, lighter soil, broken rock, solid rock. Can you count the layers? Five!”
Age 6“Topsoil is made of rotted leaves and tiny bits of broken rock. Why do you think it takes hundreds of years to make?”

Go outside: Dig a small hole in the garden and count how many worms live in one shovelful — then put them all back and fill it in.

The river right now

Water near Brussels is running low

43%

of the ten-year median for this date · 7 m³/s against 16.1 normally

low

drynormal for the dateflood

Running low for the date. Water is clear and fish are spooky, so lighter line and a longer cast earn their keep. Wading is easy; the fish noticing you is the problem. It is rising — about 294% more water by the end of the week.

Under your feet

Brussels sits on Cenozoic sedimentary rock

About 66 million years old — after the dinosaurs, as mammals and grasslands spread.

All the kinds of rock, and how each one forms →

At the surface66 million years oldNeither way
Sedimentary rock
Cenozoic sedimentary rocks · Cenozoic
What it is
The family that covers about three quarters of the land surface, in a thin skin over everything else. Some geological maps say only this much, which still tells you it will be layered and may hold fossils.
How it wears
Along its bedding planes, layer by layer, at a rate set by whatever the layers are made of — which is why sedimentary country weathers into steps.
What it means above ground
Layered country with flat-topped hills and stepped valley sides. What grows on it depends entirely on whether the beds are limey or sandy, which is the question worth asking next.
Below, layer 256 million years oldNeither way
River deposits
Eocene clay · Eocene
What it is
Alluvium: loose sediment laid down by moving water on a floodplain, a delta or a bar. Some of it is decades old rather than millions of years.
How it wears
It is already weathered; that is what it is. The river sorts it, moves it, and puts it down somewhere else.
What it means above ground
The deepest, most fertile and most level soil in any landscape, which is why floodplains are farmed and towns get built on them. Also the ground that floods, and the ground that liquefies in an earthquake.

Bedrock and soil figures are modelled from national geological surveys and global soil mapping, at a resolution of a few hundred metres — right for the shape of a district, not for a particular garden. River discharge is modelled, not gauged. For anything that matters, dig a hole and look.

The field note for Brussels, every week

One email, Sunday evening. Unsubscribe anytime.

The ground under Brussels

Brussels-Capital · Atlantic Europe

Try it

Dig down under Brussels

Drag the spade down, or tap Dig deeper, through the leaves, the living topsoil and the subsoil, all the way to the bedrock that is really down there.

About 0 cm down

The grass

the top of the ground

Under the grass is a whole hidden world. Drag the spade down — or press Dig deeper — to find out what is down there.

Layer 0 of 5

It takes hundreds of years to make one centimetre of topsoil. The depths are typical — every place is different — and the ruler is squashed at the bottom so the rock fits on the screen.

Say it like this

Age 2“Dig, dig, dig! Who lives down there? A wiggly worm!”
Age 4“Leaves, dark soil, lighter soil, broken rock, solid rock. Can you count the layers? Five!”
Age 6“Topsoil is made of rotted leaves and tiny bits of broken rock. Why do you think it takes hundreds of years to make?”

Go outside: Dig a small hole in the garden and count how many worms live in one shovelful — then put them all back and fill it in.

Try it

Dig down under Brussels

Drag the spade down, or tap Dig deeper, through the leaves, the living topsoil and the subsoil, all the way to the bedrock that is really down there.

About 0 cm down

The grass

the top of the ground

Under the grass is a whole hidden world. Drag the spade down — or press Dig deeper — to find out what is down there.

Layer 0 of 5

It takes hundreds of years to make one centimetre of topsoil. The depths are typical — every place is different — and the ruler is squashed at the bottom so the rock fits on the screen.

Say it like this

Age 2“Dig, dig, dig! Who lives down there? A wiggly worm!”
Age 4“Leaves, dark soil, lighter soil, broken rock, solid rock. Can you count the layers? Five!”
Age 6“Topsoil is made of rotted leaves and tiny bits of broken rock. Why do you think it takes hundreds of years to make?”

Go outside: Dig a small hole in the garden and count how many worms live in one shovelful — then put them all back and fill it in.

The river right now

Water near Brussels is running low

43%

of the ten-year median for this date · 7 m³/s against 16.1 normally

low

drynormal for the dateflood

Under your feet

Brussels sits on Cenozoic sedimentary rock

About 66 million years old — after the dinosaurs, as mammals and grasslands spread.

All the kinds of rock, and how each one forms →

At the surface66 million years oldNeither way
Sedimentary rock
Cenozoic sedimentary rocks · Cenozoic
What it is
The family that covers about three quarters of the land surface, in a thin skin over everything else. Some geological maps say only this much, which still tells you it will be layered and may hold fossils.
How it wears
Along its bedding planes, layer by layer, at a rate set by whatever the layers are made of — which is why sedimentary country weathers into steps.
What it means above ground
Layered country with flat-topped hills and stepped valley sides. What grows on it depends entirely on whether the beds are limey or sandy, which is the question worth asking next.
Below, layer 256 million years oldNeither way
River deposits
Eocene clay · Eocene
What it is
Alluvium: loose sediment laid down by moving water on a floodplain, a delta or a bar. Some of it is decades old rather than millions of years.
How it wears
It is already weathered; that is what it is. The river sorts it, moves it, and puts it down somewhere else.
What it means above ground
The deepest, most fertile and most level soil in any landscape, which is why floodplains are farmed and towns get built on them. Also the ground that floods, and the ground that liquefies in an earthquake.

The field note for Brussels, every week

One email, Sunday evening. Unsubscribe anytime.

The ground under Brussels

Dig down under Brussels

Water near Brussels is running low

Brussels sits on Cenozoic sedimentary rock

Sedimentary rock

River deposits

The field note for Brussels, every week

The ground under Brussels

Dig down under Brussels

Dig down under Brussels

Water near Brussels is running low

Brussels sits on Cenozoic sedimentary rock

Sedimentary rock

River deposits

The field note for Brussels, every week

Dig down under Brussels