Time gate

A time gate was a permanent physical portal through time.

There were only a handful on Faerûn and their locations were unknown to all except certain elven high mages. The gates' exact ages were unknown, but they predated even the coming of the dwarves. The gates had the power to transport an individual to any point in the past, according to the wishes of the individual walking through. If no particular period in time was thought of, then the individual was transported to a random point in the past. The effect of walking through a gate was otherwise similar to the time conduit spell.

An expedition to locate the lost time gates was launched in 404 DR.

Locations
The only mentions of the locations of the gates were made in Mystryl's ancient texts.

First gate
The first gate: "...lies hidden upon the back of the mountains, where the ice and rocks touch the summer sky of Amaunator's belt."

Amaunator's belt was a constellation appearing in the summer over the Spine of the World. The gate was within a deep cave and was guarded by a vain and greedy white dragon, who demanded a hefty fee to allow anyone past.

Second gate
The texts stated that the second gate was: "...north of Novularond, shining bright upon Misken's Peak at Highsummer."

Misken's Peak was since demolished by the Great Glacier and the portal buried beneath the ice.

Third gate
According to the texts, the third gate was on: "...Andrio's Peak near the Garden of Eldath."

The name of the peak was a misspelling by a scribe and should have referred to Mount Andrus. The garden referred to Cedarsproke, a city in the Gulthmere Forest.

Fourth gate
There was another gate located in Synnoria in the Moonshae Isles. This was not referenced in Mystryl's texts like the others, and only ten elves ever spoke about the gate in thousands of years. Its physical form was of an arch situated in a cave at the eastern end of Mirror Lake.