Zendikar, setting for the block of the same name, is a plane with powerful sources of mana, which flows differently there. Its landscape is constantly shifting and changing. This process is called The Roil. This makes settlements very scarce and only few outposts of civilization are present. Its riches in mana and other wealth has made it a destination for Planeswalkers to explore and exploit. The promise of this is also enough to lure in various local explorers and adventurers.
Another geographical feature to be noted are the large, floating polyhedron-shaped stones called hedrons that litter the landscape. Nobody is sure what they are for but their gravity-defying existence hints at the strange properties of gravity and mana on the plane.
These ancient, rune-carved monoliths are strewn across Zendikar. Up to ten miles long, some of these stones drift in the sky; others are buried in the ground, some whole, some broken. They're remnants of a lost civilization, but their original purpose is unknown. This ancient empire wielded unimaginable power—enough to suspend gravity and alter the land to suit its purposes. Trap-riddled ruins can be found on every continent. Mysterious glyphs hint at truths long forgotten. Unspeakable monsters lurk in the quiet of these hidden monuments of a forgotten past. These ruins still emanate power, and both planeswalkers and local explorers will undergo great peril to reap their rewards.
The plane is inhabited among others by goblins, elves, merfolk, humans and vampires. It is also the home of the Kor who have been abducted to other planes from Zendikar. Assorted wildlife, ranging from insects to beasts also dwells on the plane, posing another threat for explorers not to be eaten or killed by.
The plane is also the location of the prisons of the Eldrazi, an ancient and powerful race that is said to have attempted to conquer the multiverse once in the past. They were sealed away by Sorin Markov and two other ancient Planeswalkers. Now, their prisons are weakening, and their minions are breaking free. Sorin has returned to the plane to seal them away once more, though his two comrades are nowhere to be found. Nissa Revane, an elven Planeswalker from Zendikar, seems to be willing to assist him to some degree, but her goals are to see the Eldrazi imprisoned, but not on Zendikar.
Chandra Nalaar and Jace Beleren came across a scroll in Kephalai that leads to this world. Sarkhan Vol has been sent there by Nicol Bolas in search of an ancient relic. Also, Ob Nixilis, a former Planeswalker whose spark was ripped out by the erratic mana of Zendikar, currently lurks on the plane, seeking for a way to get vengeance and to restore his powers. Finally, Garruk Wildspeaker seems to have a history upon the plane, but what this means for him isn't clear.