BibTeX:
@incollection{Various,
  author = {Various},
  title = {At that time, Washington was the most racially and socially mixed},
  booktitle = {bahaistories.com archive},
  url = {https://bahaistories.com/subject/race-unity},
}

APA:
Various. At that time, Washington was the most racially and socially mixed. In *bahaistories.com archive*.

MLA:
Various. "At that time, Washington was the most racially and socially mixed." *bahaistories.com archive*, n.d..

Chicago:
Various. "At that time, Washington was the most racially and socially mixed." In *bahaistories.com archive*, n.d..