When you enter a Portal, you have the option, instead of traveling to a remote location, to enter the dungeon inside that box:

• There must be no units of any type from any player on top of the box. Other boxes may be stacked on top, but they too must not have units on them.

• The dungeon’s matching Dungeon Card (icon at the top left matches the box shape and dimensions) must be red side up.

If these requirements are met, then flip the box over (placing any stacked boxes from on top to the side). Place your unit on the Entrance space (see Exploring the Dungeon). If you have movement points remaining, you may continue moving in the dungeon.