Where was the statue of The Happy Prince situated?

The statue of the Happy Prince stands high upon a tall column, proudly overlooking the city below. And a very opulent statue it is too, sumptuously bedecked with gold leaf and precious stones. The statue is an embodiment, not just of civic pride, but of the overriding importance that the local dignitaries attach to material wealth and the values it generates. From their limited perspective down on the ground at the foot of the statue, they are unable to see the deep poverty that blights the city and the enormous suffering it brings to so many.
But from his elevated vantage point atop the tall, imposing column, the Happy Prince can see all too clearly what's really happening. As he looks with mounting sorrow at the scenes of penury and squalor around him, he sees how an attachment to material wealth has blighted the spiritual life of the city where he once lived, but which he never really knew due to his privileged, sheltered upbringing. When he was alive, the Happy Prince was as blind to the city's dark underbelly as the councillors who now stand beneath him, gazing up at his statue in blinking admiration. But now that he can see more clearly—both literally and figuratively—he's able to gain a true perspective on the myriad social problems of the city and what needs to be done to alleviate them.

The titular Happy Prince in this children's story by Oscar Wilde is a statue covered in gold leaf with sapphires for eyes and a ruby in the hilt of his sword. He is a thing of beauty thought to be entirely ornamental by the people of the town, who later determine that when he is no longer beautiful, he is no longer useful. The story is a meditation by Wilde on the theme of what makes us "useful," and he speculates as to whether the outside of a thing or person really reflects the inside.
The people of the town, being so interested in the beauty of their statue--which is also a show of wealth for the town--want the statue to be seen. As such, they have erected it "high above the city, on a tall column." This means that it is visible from everywhere in the city, and it is greatly admired. The swallow in the story decides that the statue will provide an excellent place for him to rest.