I prefer to embark next to volcanos and have the dwarves tap the volcano to make defenses (think magma traps and moats) and power furnaces and forges. Once, my

I prefer to embark next to volcanos and have the dwarves tap the volcano to make defenses (think magma traps and moats) and power furnaces and forges. Once, my dwarves built a box structure on top of their underground fortress entrance. Built a wall around that, and filled the in-between space with magma to create a sheath defense. The ingenuity of dwarves is marvelous!