In a hole in the ground there lived a hobbit. Not a nasty, dirty, wet hole, filled with the ends of worms and an oozy smell, nor yet a dry, bare, sandy hole with nothing in it to sit down on or to eat: it was a hobbit-hole, and that means comfort.
It had a perfectly round door like a porthole, painted green, with a shiny yellow brass knob in the exact middle.

A notice appeared on the gate at Bag End: no admittance except on party business.