The Iron Invasion

During today's weekly maintenance they fixed all the achievements that had their progress reset but I also noticed I was granted this title and feat of strength even though I wasn't playing WoW during MoP or WoD.

The current Blasted Lands pre-expansion world event quest line is as follows:

Alliance
Iron Horde Invasion
Attack of the Iron Horde
Under Siege
Peeking into the Portal
Subversive Scouts
Ending Executions
Investigating the Invasion
Lunatic Lieutenants
For Nethergarde!
Mementos of the Fallen
Enohar's Revenge
Death to the Dreadmaul
Toothsmash the Annihilator
Gar'mak Bladetwist
Report to the King

Horde
Iron Horde Invasion
Attack of the Iron Horde
Under Siege
Peeking into the Portal
Subversive Scouts
Ending Executions
Investigating the Invasion
Lunatic Lieutenants
Attack on Nethergarde
Ransacking Nethergarde
Okrilla's Revenge
Death to the Dreadmaul
Toothsmash the Annihilator
Gar'mak Bladetwist
Warning the Warchief

If you're level 90 and phased to the invaded Blasted Lands, but wish to see the old phase, speak to Zidormi (48.2, 7.2).

This lets you complete low level quests, and see any vendors and such.

This also shows the green version of the dark portal, which can be entered to access Hellfire Peninsula without the City portals. However, the reverse is not possible.