A History Lesson
The Arathi Highlands were once part of the Human Empire of Arathor, ruled from the city of Strom. After the "Troll Wars" in the region, the Empire formed into several city-states, and most of the citizens of Strom moved away to other cities or north to the newly established Lordaeron. Strom was turned into the fortress of Stromgarde by those that remained.
Later, during the Second War, the highlands were overrun by the Horde and Stromgarde destroyed. The village to the northeast became the Horde's outpost of Hammerfall, named for the fallen warchief Orgrim Doomhammer.
The humans of Stromgarde rebuilt the city, only to be forced to flee when attacked by Ogres and Syndicate. The Alliance now take shelter in a chasm to the northeast of the city, known as Refuge Pointe (and not, as some people call it, Refugee Point).
Exploration
Aefa started on the north-eastern side of the Highlands, entering from Hillsbrad Foothills through the damaged gate in Thoradin's Wall. Historians are unclear as to when the wall was built, possibly during the Troll Wars, but these days it is a crumbling ruin.
Thoradin's Wall
On the south side of the road leading across the Highlands is the ruined city of Stromgarde Keep. The city is now occupied with Ogres and Syndicate Humans.
Stromgarde Keep
All areas of the Keep are hostile to members of the Horde, but one section of the Keep is still held by the Stromgarde military and the vendors there be accessed by Alliance. If I remember correctly, it used to be where the Alliance purchased their Mageweave and Heavy Mageweave Bandage manuals, although they are no longer required. Where did the Horde used to buy them?
The Alliance-held section of Stromgarde
Can't see much of Refuge Pointe from this angle...
Hammerfall is the Horde stronghold in the Highlands. The small town is surrounded by a wooden palisade.
Road to Hammerfall
The Horde's entrance to the battleground of Arathi Basin is in the mountains behind Hammerfall.
Arathi Basin entrance, Horde
In locations throughout the zone, there are stone circles guarded by elementals. These must be visited as part of a quest to free Princess Myzrael from her prison, and leads into a long chain around the zone (starts with [The Princess Trapped]).
Start point for the Princess Myzrael quest chain
Along the southern edge of the zone lies the canal that separates Arathi Highlands from Wetlands, or Lordaeron from Khaz Modan. Near where the mouth empties into the sea, the Drowned Reef has claimed a few ships, the wrecks of which lie underwater. One ship made it to land though - the Harbinger is anchored in Faldir's Cove and members of the crew there give quests for Booty Bay reputation. The cove can be reached through a tunnel on the southeast side of Stromgarde Keep.
The Harbinger
There are a number of farms around the Highlands. Some are controlled by Syndicate, but Go'Shek Farm not far from Hammerfall is controlled by the Horde.
Go'Shek Farm
Witherbark Village is the stronghold of the Trolls in the Highlands and is located in the slightly more forested area in the southeast of the zone.
Witherbark Village
The Witherbark trolls are in alliance with the Boulderfist Ogres who also live in caves around the zone. Boulderfist Hall is not far from Witherbark Village.
Boulderfist Hall
To leave the Highlands to the south, you must pass over the Thandol Span - a huge Dwarven bridge linking the Highlands with the Wetlands. There were originally two bridges here, but one was damaged badly during an attack by the Dark Iron Dwarves.
Thandol Span
There are Dark Iron Dwarves still nearby with carts of explosives - an attempt to blow up the second bridge?
Dark Iron Dwarven Sappers
In Cataclysm
Arathi Highlands is not earmarked to be changed significantly when the Cataclysm comes, but that doesn't mean the inhabitants, animal and humanoid, won't be affected. Perhaps the Elementals at the rings of binding will disappear? Will the Horde pull out of the area or the Alliance manage to take back part of the old Keep? None of these things are expected to happen but for a zone so rich in Lore, it would be a shame for it to be ignored completely.
Do you have fond memories of traveling in Arathi Highlands? I enjoyed the quests here as Horde, although the travel three or four times between Hammerfall and Stromgarde gets old after a while, especially if you aren't level 40 yet to get your fast mount. It would have been twice as painful when the first mount was at level 40!