The Eastern Gate of Jerusalem, sometimes referred to as the "Golden Gate", was sealed up by the Ottoman Sultan Suleiman the Magnificent in 1541.  It is also known as the "Gate of Mercy", "Gate of Eternal Life", and the "Beautiful Gate".  It is through this gate that Christ will pass into Jerusalem at His second coming, after which it will be torn down and replaced with a new gate.  It's uncertain how the gate will be opened when Christ approaches the city, but it's guaranteed that it will open for Him.  It may be the means by which it's opened that facilitates its replacement, and its replacement may instead be part of a much larger symbolic meaning and purpose.