Squadpack Modpack: El Quattro

 If playing single player, when creating a new world, go to more world options and change the world type to Lost Cities. Then click on customize to select what type of city.

If playing on a server, change the world type in the server properties file to lostcities.  If you want to customize, you have to add a line generator-settings={"profile":"nodamage"} The profile is different for each custom city.