You introduced a lovely pale translucency with the very light cyan in front of the building. Hwever it seems to want to escape just the right side of the picture, and move across the ground plane somehow into distance. A river? An icy plane? You know how to find the horizon line, right? Just where any 2 of the horizontal lines on your facade and steps meet, somewhere to the left vanishing point. That point will be on the horizon line. After you know where that is you can go from there in terms of finishing the pic any way you want. See? Nice weird people/aliens.