Property

Our property consists of the following (in thousands):



	March 31, 2017		December 31, 2016
Land	$	1,112,752	$	1,107,072
Land held for development	73,996		82,953
Land under development	48,220		51,761
Buildings and improvements	3,432,320		3,489,685
Construction in-progress	80,059		57,674
Total	$	4,747,347	$	4,789,145

During the three months ended March 31, 2017, we sold three centers and other property. Aggregate gross sales proceeds from these transactions approximated $54.5 million and generated gains of approximately $15.8 million. Also, during the three months ended March 31, 2017, we invested $30.4 million in new development projects, which includes the purchase of the retail portion of a mixed-use project in Seattle, Washington that was subject to a contractual obligation at December 31, 2016.

At March 31, 2017, one center, totaling $37.3 million before accumulated depreciation, was classified as held for sale. At December 31, 2016, one center, totaling $1.6 million before accumulated depreciation, was classified as held for sale. Neither of these centers qualified to be reported in discontinued operations, and each has been sold subsequent to the applicable reporting period.