The Golden Gate was built along with the 55 Window Palace in 1754 and is highly regarded as Nepal's most important piece of artwork. Made from gilded copper work it's incredible ornate and you may pass through it on the way to the Palace via Bhaktapur Durbar Square.
In the carved pediment above the outer door frame is Vishnu's Garuda and it is shown disposing of a number of serpents (Garuda's sworn enemies.) A four-headed and 10-armed figure of the goddess Taleju Bhawani is just one of the featured mythical creatures of surrounding The Golden Gate directly above the door.
Read more about The Golden Gate in this guide to the 55 Window Palace.