When people talk about Baltimoreโ€™s vacant real estate, theyโ€™re usually referring to the blocks of dilapidated rowhouses in some of the cityโ€™s hard-hit neighborhoods. But thereโ€™s another kind of structure that worries city planners:  the 1970s-era office tower.

โ€œSeveral Downtown buildings do not meet todayโ€™s standards and are considered functionally obsolete for office use, even with substantial investment,โ€ according to the Office Vacancy Task Force. Which is a big problem, since Baltimoreโ€™s tallest building โ€” 100 Light Street, the former Legg Mason building โ€” is one of those outdated models. โ€œStuck in between the perceived coolness of early 20th century facades and the newness of all-glass towers,โ€ Mark Byrnes writes in the Atlantic Cities blog, โ€œthese buildings are having a hard time retaining existing tenants, let alone attracting new ones.โ€

Another worrisome structure is 2 Hopkins Plaza, built in 1970 and smack in the middle of the Inner Harbor. Itโ€™s currently 42 percent vacant, and thatโ€™s including PNC Bank, which is scheduled to move out this summer. Some developers hope that renovations and mixed-use use residential conversions will save the buildings. Or does something more drastic need to be done?