Silent Realms are locations in Skyward Sword. Link is able to access the Silent Realm through the Goddess Sword, by stabbing a Trial Gate within each of the four main territories of the game; Faron Woods, Eldin Volcano, Lanayru Desert, and Skyloft. While in the Silent Realm, Link is weaponless and in spirit form. His goal here is to collect 15 Sacred Tears. The Sacred Tears are from each of the Golden Goddesses and Hylia. The moment Link steps out beyond the protective circle around the Trial Gate, the Guardians of the Silent Realm will awaken, and will attack him. If they are successful, Link's spirit will shatter and he will have to start the trial over again.
Every time Link finds a Sacred Tear, he will temporarily stun the Guardians for 90 seconds, in which he is free to move around without being attacked. However, Link cannot stop the Watchers. These guards float around the area with a lantern, and if they catch Link inside their light, the Guardians will be awakened and in turn pursue Link.
In each Silent Realm, there are two items that appear that cannot be found anywhere else within the game. The first of these would be Light Fruit. If Link collects one of these, he can use it to create a beam of light above every Sacred Tear, making it easier to see their position. However, the beams only last for 30 seconds, and once the time is up, Link will have to find another Light Fruit to re-create the beams. Also, Link can find Dusk Relics in the Silent Realm. These are very similar in appearance to Amber Relic in terms of size and shape, but differ in color. They can be used to upgrade Link's equipment at the Scrap Shop.