@SubscribeEvent
 public void clearOnUnload(WorldEvent.Unload evt) {
   PylonFinder.stopAllSearches();
   int dim = evt.world.provider.dimensionId;
   ChromatiCraft.logger.debug("Unloading dimension " + dim + ", clearing crystal network.");
   try {
     this.clear(dim);
     for (WorldLocation c : tiles.keySet()) {
       CrystalNetworkTile te = tiles.get(c);
       PylonFinder.removePathsWithTile(te);
       if (te instanceof CrystalTransmitter) ((CrystalTransmitter) te).clearTargets(true);
     }
     tiles.removeWorld(evt.world);
     for (TileEntityCache c : pylons.values()) c.removeWorld(evt.world);
   } catch (ConcurrentModificationException e) {
     ChromatiCraft.logger.logError(
         "Clearing the crystal network on world unload caused a CME. This is indicative of a deeper problem.");
     e.printStackTrace();
   }
 }