I live in northern Europe in a very wooden house

Have you ever built a house out of Legos? It's just like that.

Why not? Pretty much everything except the roof structure is made of bricks. My house is entirely bricks; an outer and an inner wall separated by a gap with insulation, with a wooden skeleton for the roof secured to the brick walls. All interior walls are either made of bricks (the originals built with the house in the 60's) or aerated concrete blocks (added in a refurbishing later in the 00's).

From South America. Our homes are brick and concrete, with a steel structure made of thick wires. If you’ve seen a mall being built, that, but smaller. Allows you to build up, while being resistant to earthquakes

what’s the structure of the house made out of?

Reinforced concrete. It's cheap to create, the materials are quite cheap, it's very strong, and you can make it have any shape.

I never understood why the US makes strctural bits out of wood. I can understand using it on the walls, but it's completely unfit for the structure.

I'd bet most people here claiming their houses are made of bricks have a reinforced concrete structure hidden inside brick molds on the corners.

Brick does really badly in earthquakes, at least without major reinforcing. 'Unreinforced masonry' can be fatal pretty easily.

Brick veneer over timber framing can be a thing.