How did topography influence migration and invasion routes into Europe?

Topography influenced migration and invasion routes into Europe by creating natural barriers such as mountains, rivers, and seas that directed the movement of peoples. These geographic features could funnel travelers along specific pathways or impede their progress, affecting the speed and success of migrations and invasions. Regions with more open terrain were often more susceptible to incursions, while mountain ranges and bodies of water could act as protective barriers.