When Bungie finally revealed Destiny 2, they said that one of the ways they were making the world more interesting was something called Lost Sectors, which are well-hidden areas you'll have to find without getting much help from your map.
Find one of them, and you'll also find plenty of enemies, and succeeding in killing them all will earn you a cache code that can be used to open a special loot chest hidden in the same area. Opening this will hopefully earn you some better looking and stronger gear. Sounds good, doesn't it? Welll, now you can see the feature explained in the gameplay trailer below.
Will these be among your priorities in Destiny 2?