Property

Our property consists of the following (in thousands):



	June 30, 2017		December 31, 2016
Land	$	1,109,163	$	1,107,072
Land held for development	72,009		82,953
Land under development	48,780		51,761
Buildings and improvements	3,411,373		3,489,685
Construction in-progress	82,575		57,674
Total	$	4,723,900	$	4,789,145

During the six months ended June 30, 2017, we sold six centers and other property. Aggregate gross sales proceeds from these transactions approximated $113.1 million and generated gains of approximately $48.0 million. Also, during the six months ended June 30, 2017, we invested $33.5 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 June 30, 2017, two centers, totaling $27.1 million before accumulated depreciation, were classified as held for sale. At December 31, 2016, one center, totaling $1.6 million before accumulated depreciation, was classified as held for sale. None of these centers qualified to be reported in discontinued operations, and each has been sold subsequent to the end of the applicable reporting period.