Arriving at the waypoint triggers a short scene which unlocks all challenges in the city, allowing Spider-Man to collect Challenge Tokens (which he can use to craft more suits, gadgets, and upgrades) upon completion. Some of the Challenge objectives vary, this one being a Bomb Challenge; accept it to begin a mission in which Spider-Man must dispose of three bombs as quickly as possible.
The first bomb is on the ground by a train (hold + to swing it around, then tap rapidly to defuse it), the second is by the docks, on the porch of a building, and the third is on a dock. To reach the third, Spider-Man will have to cross a big body of water, where there are only a few cranes that he can swing from. To avoid falling in the water and maintain speed, use + to zip to points highlighted by a small white circle, then to bounce off those points with a burst of speed. Unlock the Point Launch Boost skill to aid in this and future Bomb Challenges.
Upon completion of the Challenge, Spider-Man receives Challenge Tokens depending on how quick he was, the least being one and the most being three. If you do not have the necessary skills to complete this challenge quickly, you can always return to it and try again. For more tips on how best to achieve the maximum amount of tokens for this and other challenges, see the Challenges page. This mission is followed by a call from the mysterious man who has set up these challenges, and that is then followed by a call from MJ that leads into the next mission.