Opinions abound over the development of “Millikan on Mass,” apartments now under construction in the 500 block of Massachusetts Avenue and the removal of the green space surrounding the Barton Apartments. Insight Development Corp., the nonprofit development arm of the Indianapolis Housing Agency, breaks ground this week on infill apartments and retail to surround the 21-story Brutalist-style tower. Opponents argued for preservation of the tree-lined park setting as planned by architect Evans Woollen. New development will obscure the as yet under-appreciated modernist concrete structure, not to mention the blocked light and view for the lower-level tower residents. Some favor development, but feel that the design does not blend or enhance the iconic tower. Supporters believe that the tower was poorly placed originally and that the city needs more density. Located across from the set-back Indianapolis Fire Station and Credit Union (soon to be replaced with apartments and retail space), this block is seen by some as a gap interrupting the flow and vitality of the Mass Ave Cultural District filled with restaurants, shops, galleries, and theaters. As downtown has redeveloped, many residents and businesses have campaigned for the dead block to be filled. Regardless of your view, this post looks at what occupied the 500 block in the past and encourages comments about the project or memories of the older buildings  removed in the 1950s and ’60s.