Property

Our property consisted of the following (in thousands):



	December 31,
	2013		2012
Land	$	854,409	$	881,156
Land held for development	116,935		121,294
Land under development	4,262		6,155
Buildings and improvements	3,238,817		3,325,793
Construction in-progress	74,853		65,452
Total	$	4,289,276	$	4,399,850

During the year ended December 31, 2013, we acquired three centers and other property for approximately $153.6 million, invested $19.3 million in new development projects and acquired our partner's 50% interest in an unconsolidated real estate joint venture, which increased property by $64.2 million (see Note 23 for additional information).

During the year ended December 31, 2013, we sold 20 centers and other property. Aggregate gross sales proceeds from these transactions approximated $233.9 million and generated gains of $120.0 million.

Also, eight properties totaling $155.0 million before accumulated depreciation were classified as held for sale as of December 31, 2013 (see Note 15 for additional information).