Christopher Alexander has much more to say about entrances than I will, and you will want to consult A Pattern Language on this point.
Entrances are, of course, related to gates and can sometimes even be difficult to distinguish from them, and the distinction may at times be arbitrary.
Entrances to important civic, sectarian, and commercial buildings should be immediately identifiable at a distance and should state something about the nature of the undertaking. They should not intimidate those seeing or entering the building (unless, I suppose, we are talking about the headquarters of the KGB or the FBI).
If a building is to be a good neighbor to the district in which it finds itself, it ought really to offer some amenity, aesthetic or practical, to the locale that hosts it.
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