This pack, one of six included in the Civilization VI: New Frontier Pass, adds João III as the leader of Portugal. Portugal excels at establishing international Trade Routes, expanding naval exploration, and using its unique Nau naval melee unit to dominate the seas. 

The Portugal Pack also adds the Zombies Defense game mode, Wetlands maps, and two new World Wonders. More details below: 

Portugal

• Unique Civ Ability: Portugal’s unique ability, "Casa Da Índia," significantly increases the yields of International Trade Routes, but limits those routes to cities that are on the coast or have a Harbor. This ability also grants Trader units additional range and the ability to embark on water tiles as soon as they’re unlocked.
• Unique Leader Ability: Joao’s unique "Porta Do Cerco" ability grants all units increased Sight. It also increases Trade Route capacity whenever Portugal meets a new civ, and provides Open Borders with all city-states.
• Unique Unit: Portugal’s unique unit, the Nau, is a naval melee unit that replaces the Caravel. It starts with one free Promotion, requires less maintenance than the Caravel, and has two charges to build Feitoria shipping ports unique to Portugal.
• Unique Infrastructure: The Feitoria can only be built by a Nau unit on a foreign City’s coastal tile next to a Luxury or bonus resource. Sending a Trade Route to a City with a Feitoria provides Portugal with additional Gold and Production.
• Unique Building: The Navigation School replaces the University building and increases Production toward naval units in each City where it's built. It also grants additional Great Admiral points and increases a City’s Science yield for every two coastal or lake tiles within its borders.

Zombies Defense Game Mode

In this optional game mode, the dead don’t stay dead for long, presenting an ever-growing threat to the world’s civilizations.

• The Dead Don’t Rest: Every unit has a chance to respawn as a ravenous Zombie when it dies. Zombie units hunger after and attack the nearest non-Zombie unit; any units they slay succumb to the infection and respawn as Zombies themselves.
• The Living Fight Back: An arsenal of new trap and barricade improvements that can be built in owned and neutral territory deal damage to passing hostile units. Zombies mindlessly searching for their next brain banquet fall victim to these improvements and can never pillage them.
• Humanity Takes Control: Two new projects allow civilizations to temporarily subjugate Zombie units within a City’s limits, putting them under player control:
  • The "Holy Site: Turn Undead" project unlocks early, but controls Zombies only briefly.
  • The "Campus: Dark Signal" project unlocks later in the game, but grants additional turns with which to command Zombies’ mindless mayhem.
• Meanwhile, the “Zombie Outbreak” spy operation attempts to spawn Zombies on worked tiles in another player’s city.

Additional New Content

• Wetlands Map Type: Squelch your way to victory through a soggy map dominated by Marshes. This map offers new strategic challenges and defensive possibilities: while Marshes penalize Movement, careful positioning can allow ranged units to exploit your enemies’ reduced speed.
• Torre de Belém World Wonder: This imposing tower historically served as a ceremonial gateway to Lisbon, and grants additional Gold and Great Admiral Points. International Trade Routes embarking from this City receive additional Gold for every Luxury Resource at the destination. When constructed, any Cities owned by the civilization but located on other continents receive the cheapest Building they can construct at that time.
• Etemenanki World Wonder: The name of this Babylonian ziggurat translates to "temple of the foundation of heaven and earth." It grants additional Science yields every turn, as well as bonus Science and Production to all Marsh tiles in that civilization and Floodplains in the City that builds it.