In World of Warcraft where is the portal in Silvermoon city to teleport to the Undercity???

If you bring up the map of silvermoon city with "m". The Sunfury spire is at the north section. Once you enter the spire you can take the ramp on either side up to the middle of the room and then continue to the back room and up that ramp. You will see a glowing red orb..right click and shablam..your in the ruins of lordaeron.