If a wall has a beam, column, or other wall directly below or following the same path, it is a load-bearing wall. Walls more than 15 cm thick are usually load-bearing walls. The walls at the center of a building usually support most of the roof's weight. If there is no supporting structure under the wall, the wall may not withstand loads.
If the wall is, in fact, load-bearing and there is no supporting structure, this part of the house is in danger of collapsing. A) Look at any wall you think you'll want to remove. If the drywall is open, this process will be much easier.
