About a year of construction remains for two apartment towers replacing a Crystal City office building. The final beam was placed atop the two residential towers at 2000 and 2001 S. Bell Street, formerly Crystal Plaza One, this week. Developer JBG Smith and its project manager, Balfour Beatty, announced the "topping out" construction milestone on The two multi-family residential towers replacing the Crystal Plaza One office building are nearing completion, with about a year left to go.