All my models are see through and I can't figure out why. For example:
Here's what it looks like when you are not looking through them:

And when I look through one of them:

Why can I see the black cube through the other Model? It's the same the other way around. I can see the gray object through the black cube. I draw the models like this:
public void Draw(GraphicsDevice graphicsDevice)
{
foreach (ModelMesh mesh in model.Meshes)
{
foreach (BasicEffect effect in mesh.Effects)
{
effect.View = camera.View;
effect.World = worldMatrix;
effect.Projection = camera.Projection;
mesh.Draw();
// Debug: Draw bounding boxes
modelBox.Draw(effect, camera.View, camera.Projection, effect.World, graphicsDevice);
}
}
}
What am I doing wrong?
More screenshots: https://i.sstatic.net/cZYJT.jpg, https://i.sstatic.net/w84bL.jpg

