you’ll find Valdrakken’s portal trainer, Alregosa. She can be found near a floating book, next to the two dragonkin channeling a portal to Stormwind City.
In Stormwind, for example, you appear inside the mage tower at the center of the Mage Quarter. You cannot learn the portal spells of the opposing faction. Portal cannot be cast in combat. In addition, portals cannot be cast inside PvP battlegrounds. There is a second portal trainer in Sh...
Blizzard has updated the lighting in the Stormwind Portal room in the Shadowlands expansion. Heres a look at the lighting before the update, taken from live servers, and the Shadowlands pre-patch. (Source)