There are several landmarks from TES V: Skyrim that have been recreated in ESO: Markarth's version of the Reach, but are not normally accessible. They are shown on the map, but not named in-game, so they are listed here by their names from Skyrim.
PlacesEdit
ArkgnthamzEdit
A Dwemer ruin found west of Valthume, guarded by a few Dwarven automatons. The entrance is blocked by rubble and cannot be accessed.
Castle Thorn TowerEdit
A tower of Castle Thorn is found northwest of Deep Folk Crossing; it also exists in Western Skyrim. It represents the only structure of Castle Thorn visible from beyond the mountains.
Reachwater RockEdit
The waterfall entrance hidden inside the Reachwater River is located to the southwest of the Rebel's Retreat, but the tunnels behind it cannot be entered.
Sky Haven TempleEdit
Sky Haven Temple can be seen atop Karthspire, an inaccessible mountain in the middle of the Karth River. Unlike in Skyrim, it cannot be reached from Rebel's Retreat.
Sundered TowersEdit
Sundered Towers are inaccessible from the Reach and are seen in the distance. The instanced version is visited in Red Eagle Ridge, accessed from Western Skyrim.