If you're talking about in twilight princess, there is a lake bed temple. Complete all the steps to the temple. You should eventually end up in an underwater maze. At the end, there is a room with three spider web covered holes in the floor. Cut the one in the middle, fall through, and the boss' key should be beneath you.
check the map at telmas bar. it will mark his location on ur map.
The Hylian field is the big field that you first see when you come out of the Kokiri forest. In it's centre is Lon Lon Ranch, and from the field you can go to Lake Hylia, Gerudo Valley, Hyrule market town, Kakariko Village, Lon Lon Ranch, Kokiri Forest, or Zora's River.
The big key
the variations of the big goron sword
Find the big key.
Throw the nearby bobm-bugs in it.
Warp to Death Mountain. There will be a big, tall rock stuck in the ground. Go over to it and the Midna icon will appear. Talk to her and she will warp it back to the Zora village... just watch what happens from there it's kinda cool.
it is in the ice cavern in zoras domain
That is saria's song
if your talking about link to the past, at the edge of lake hylia, there is a bombable cave, go inside and you wwill see a big chest. go back outside and bomb the areas to the left until a secret door shows up, go inside and receive the ice rod yays!
There are 4 bottles available to obtain in the Legend of Zelda Ocarina of Time and you can recieve them by doing the following: Find the 3 super cuckoos in the super cuckoo minigame at Lon Lon Ranch, Find all of the cuckoos and bring them back to there pen in Kakariko Village then talk to the lady by the pen, Dive underwater near Zora's Domain at Lake Hylia to find a bottle with a letter inside show it to King Zora in Zora's Domain and he will let you keep the bottle, Find all of the Big Poes scattered around Hyrule and show them to the Poe collector in the Market (she's in the first door by the entrance).
That building that's twice as big as a house. What more can i say?