When rock from the mantle melts, moves to the surface through the crust, and releases pent-up gases, volcanoes erupt. Extremely high temperature and pressure cause the rock to melt and become liquid rock or magma. When a large body of magma has formed, it rises thorugh the denser rock layers toward Earth's surface
I'm pretty sure it's railroads, because there's not that many highways in Siberia, the rivers would be frozen over, and there's not a ton of people in Siberia. I'm sorry if I'm wrong.
<em>Dublin, Ireland is the Largest city in it's country or region. I'm Irish, so this really hit close to home.</em>