'Sacred lily' generally refers to either a water lily or Rohdea japonica, which looks completely different as well.
Is that in a pot or in the ground? It looks very much like a type of Amaryllis, which grows from a bulb and is only winter hardy in zones 9+. Is it in a public garden?
They are often grown as houseplants though and can be carefully coaxed back into bloom, which usually happens in the winter. We'd expect those thick flower stems to be hollow and drippy when cut.
Two or three of these were planted at some point in the past at Georgetown Lutheran Church at the corner of Wisconsin Avenue and Volta Place. I started taking care of the garden as a volunteer last fall. It had not been tended in several years. A former member had a landscaping business and whenever one of his clients didn't want something, he planted it at the church. The plants have certainly not been babied along!
We do think it is some type of Amaryllis, based on the flower and bud shape. There are several different varieties. Normally they are not something that overwinters here but in Washington, DC you are in a warmer and more protected environment, so it is possible.