Tallnecks are how you unveil the map in the Horizon games. They are massive machines that are completely harmless unless you happen to walk under their feet. Whenever you find one, you need to climb to the top of it and override it to unveil the map. Here is how you override the Stand of the Sentinels Tall in Horizon Forbidden West.
This Tallneck is on the far western side of the map in the jungle biome. You will be able to get it on your map by talking to someone in a town that has rumors. You can also find it by following the coastline north once you reach it. The Tallneck walks around a series of tree forts that you must maneuver around to reach the top.
When you reach the area, start your climb by going to the center of the area and jumping across the bridge. Use your Pullcaster to reach the other side. Make a left and follow the path until it abruptly stops. Use your glider to reach the bars on the tree across from you. While you are climbing to the platform in this tree, Stalkers will appear. If you need to, take them out and then come back when they are defeated.
After you reach the platform on the tree, cross the bridge to the next platform. Once there, you will see a log that you can jump down to. Jump down and continue forward to reach the next platform. With nowhere else to go, wait for the Tallneck to circle around and jump on the handhold at the base of its neck.
Jump over to the other side of the Tallneck and wait until you reach a tree platform with a rope on the edge of it. Jump off the Tallneck to grab hold of the ledge and pull yourself up to the next platform. Use the ropes to cross to the next platform. After that, you will need to cross another set of logs and then another rope. Follow the course until you reach the platform with the Clamberjaw.
You will need to fight two Clamberjaws on a platform that has an upper and lower level. After the fight, find the ladder that is hanging from an upper platform. Shoot it down and use it to climb up. At the top of the ladder, use the zipline to get to the next platform. At the bottom of the zipline, climb the tree to the top platform. Follow the route across the platforms and over the broken bridge. When you reach the last platform, you will be close enough to jump onto the Tallneck’s head when it comes around again.
