Paradise comes from the Greek paradeisos, “surrounded by walls”. In Madonna Laboris Mary labors in seclusion at the borders of Paradise, providing her scarf for souls to ascend behind its walls. “All day long I watch the gates of Paradise; I do not let anyone in, yet in the morning there are newcomers in Paradise,” Saint Peter complains to the Lord. The Lord and Peter make night rounds and see Mary with her scarf and the Lord bids Peter to “let (Mary) be”.
That paradise means surrounded by walls rather than walls being something that surround paradise is particular. Paradise as adjective instead of paradise as noun. You can go to a place that is paradise, but you cannot go to paradise.
Many things in today’s world are surrounded by walls and we would not call them paradise. But if we were good students of etymology we would.