What are ziplines and power line towers, and how do I use them to travel?

Ziplines and power line towers:

• Tall metal power line towers are placed across the map, connected by wires that stretch over forests, fields, and hills.
• You can use these wires as ziplines to travel quickly between towers at height.
• While riding a zipline, you fly over the landscape, which gives you both a speed advantage and a bird's-eye view of the area below.
• The towers themselves have platforms with loot crates and barrels, making them worth visiting even if you don't need to travel.
• Be careful though - you are exposed and easy to spot from the ground while on a zipline or standing on a tower.