After reaching level 68, there were more new Instance Dungeons to attempt.
Netherstorm had three five-person Instance Dungeons and one 25-man Instance Dungeon. The three five-person Instance Dungeons were Arcatraz, The Botanica and The Mechanar, while the 25-man Instance Dungeon was The Eye, where Kael'thas Sunstrider resided.
Of these Instance Dungeons, Arcatraz required a key to be able to enter.
The key wasn't hard to obtain, but these Instance Dungeons had additional conditions.
If players wanted to attempt these Instance Dungeons, they needed to travel into the sky.
Here, the importance of having a flying mount was made apparent. If you didn't have a flying mount, you couldn't even enter into the Instance Dungeon. If others saw that you didn't have a flying mount, they wouldn't join up with you.
Alternatively, a Warlock could use a Summoning Portal to transport the team, but not every team had a Warlock.
