The Goliath is the premier event of the Horizon Festival Mexico adventure chapter, and will test your stamina and racing will in Forza Horizon 5. In order to unlock The Goliath, however, you will need to complete a number of tasks in order to begin your final quest in this chapter.
First off, you will need to begin and complete the introduction portion of FH5. This includes completing the intro in which you arrive at the Horizon Festival, and finishing enough Accolades in order to unlock the actual Horizon Adventure.
It is at this point where you will be able to unlock The Goliath. You won’t have to fully complete chapter from other outposts, nor all the chapters in the Horizon Festival one itself.
We should note that it won’t be instantaneous, as unlocking the actual chapter will require grinding through Accolades in order to get enough points and acquire new chapters. More information on that can be found via the link below.
To go to the event, you will want to drive to the southeastern part of the map.
The Goliath can be found near the Riviera Maya region of the FH5 map, at the Playa Azul. Those who complete, and win the Goliath will receive 4,000 Accolade points.