Sahasra Slope Cave
Tears of the Kingdom
The cave can be found just beneath the Sahasra Slope Skyview Tower. The cave is blocked with tons of boulders. Link can use Bomb Flowers to blast through the cave, or alternatively, use Fuse with nearby rocks and boulders to break through. As Link breaks the boulders he'll find more items, such as Rusty Claymores and Traveler's Claymores that he can fuse with rocks.
Inside, Link will find a trio of Horriblin, including a more dangerous Blue Horriblin. A Treasure Chest can be found here which contains a Shield of the Mind's Eye. Deeper in the cave, behind a larger rock, Link will encounter a Bubbulfrog as well as find a Rare Ore Deposit.
In order to gain entrance to the Sahasra Slope Skyview Tower, Link will need to travel down into the Cave. While underneath the tower, Link can use the Ascend ability to glide up into the Tower. There he can move both of the Long Sticks that are blocking the door, so it will now slide open. Billson could then do the repairs and Link will be able to use the Tower.