It seems as though the constant changes were setting the table for Chapter 3 Season 2, as the latest update has completely altered the state of play. In one of the biggest developments since the title was released, Epic Games has removed building from Fortnite, at least for the time being.
With no building feature currently available for players to protect themselves in Fortnite, some may look for alternative travel routes to avoid popular areas. To help balance things out, Epic Games have added in new Siege Cannons, which allow players to launch themselves through the air and have the option to deploy their gliders and travel even further.
Players won't take fall damage if they do not deploy their gliders, so the Siege Cannon, on paper, has a very similar effect as Launch Pads. Siege Cannons can also be used offensively to fire projectiles (when no player is loaded in the cannon) at nearby opponents.
To use a Siege Cannon in Fortnite, approach the new machine and press the prompted button on the screen to interact (Enter). Players will then be given the option to Fire, Aim (Load Self), or Exit the Siege Cannon.
Once you have loaded yourself into the cannon, point to where you're aiming to travel and launch yourself through the air with the Fire control. In order to travel further through the air, aim the Siege Cannon higher before launching and deploy your glider at the highest point.
Siege Cannons are located throughout the Chapter 3 Season 2 Fortnite map in various IO-controlled locations. In total, six different map locations contain Siege Cannons for players to use, and they are nicely spread around the island for travel purposes.
Here's where to find Siege Cannons in Fortnite Chapter 3 Season 2.