Hall of the Polychromatic

No one really knows why the Ancient Visitors insisted on building the Hall, only that they viewed it important for their own religions. After years of lying abandoned after their departure the plant life began to overtake the building itself as it should have. After a time however a discovery was made by two children looking for adventure. They wandered in through a hole created in one of the walls only to discover that the colorful windows of the building remained in tact, if a bit dirty. More interesting was the affect those windows had on the plant life that was working to reclaim the building for the land.
We haven't yet been able to fully understand why it happens, as we cannot dismantle one of the windows in order to study it's properties. Our strongest theory is that the minerals used to create and dye the glass interacts in a unique way with our sun. This causes strange effects on the plants inside if given sufficient time. So now the Hall of the Polychromatic exists to serve as a greenhouse for what can only be described as luxury plant life. The plants react to the color of the light they fall under by taking on tones from the light itself. The strongest reaction is, of course, seen in white flowering plants and so these are given prime locations where multiple colors meet more consistently in the room, for the longest period of time. By carefully cultivating perennial flowering plants in these locations the results are flowers that exhibit a multitude of colors, much like the windows that provide the effect. These flowers are the most rare of the Hall and so not all of them are sold. Some that have been cared for long enough to retain the effect are transplanted to public scientific gardens or other learning environments. Others are reserved so the flowers may be clipped and sold, usually at a cost that makes them a luxury afforded only for very special events, or more regularly by the more wealthy.