From Compendium of Worldly Lore
Horizon Walker is funky. It is the perfect class for a planar campaign and one that travels all over the world and tour the globe. It gains some extra points in given skills depending on the terrain. It's a pretty cool prestige to dip into.
Role: DPS
Characteristics: A DPS that can fight in a variety of different terrains
Source: Dungeon Master's Guide
Game Rule Information
The Horizon Walker has the following game statistics.
Abilities: Strength or Dexterity for combat and Wisdom for the survival skills you need.
Alignment: Any
Hit Die: d8
Starting Gold: N/A
Class Skills
The Horizon Walker's class skills are Balance (Dex), Climb (Str), Diplomacy (Cha), Handle Animal (Cha), Hide (Dex), Knowledge (geography) (Int), Listen (Wis), Move Silently (Dex), Profession (Wis), Ride (Dex), Search (Int), Spot (Wis), and Wilderness Lore (Wis)
Skill Points at 1st Level: (4 + Int modifier) × 4
Skill Points at Each Additional Level: 4 + Int modifier
Class Features
All of the following are class features of the Horizon Walker.
Weapon and Armor Proficiency: A Horizon Walker is proficient with gain no proficiency with any weapon or armor.
Terrain Mastery: At each level, the Horizon Walker adds a new terrain environment to their repertoire from those given below. Terrain mastery gives a horizon walker a bonus on checks involving a skill useful in that terrain, or some other appropriate benefit. A horizon walker also knows how to fight dangerous creatures typically found in that terrain, gaining a +1 insight bonus on attack rolls and damage rolls against creatures with that terrain mentioned in the Environment entry of their descriptions. The horizon walker only gains the bonus if the creature description specifically lists the terrain type.
Horizon walkers take their terrain mastery with them wherever they go. They retain their terrain mastery bonuses on skill checks, attack rolls, and damage rolls whether they’re actually in the relevant terrain or not.
Planar Terrain Mastery: Planar terrain mastery functions just like terrain mastery, except that the horizon walker can choose one of the planar categories at each level. The horizon walker can take a non-planar terrain type instead, if she wishes.