High Risk Wilderness Worlds were worlds that were added to the game with the Free Trade and Wilderness update on 1 February 2011. These worlds replaced the Bounty worlds (+1) and PvP Worlds. World 137 was a High Risk Wilderness world prior to their removal.
Whilst in the Wilderness on these worlds Protect Item is inactive and if you die you will lose your items. Going onto these worlds can be a risky, but good way to make money if you have got a high Combat Level with good armour and weapons; it is highly recommended that you only take items into the Wilderness that you are prepared to lose! With the Protect Item prayer being disabled in the wilderness caution is to be taken into consideration throughout.
You will always get the items your opponent was wearing, wielding and carrying upon killing them, unless the item(s) was untradeable, in which case will usually turn into a stack of gold coins according to its value.
A warning is shown on attempting to log-in to a high risk world from the lobby. This is not seen when using "join" or returning to the world from the lobby. Upon log-in a second warning is shown in the form of a chatbox message.