Property, net:

Property at December 31, 2015 and 2014 consists of the following:



	2015			2014
Land	$	1,894,717		$	2,242,291
Buildings and improvements	7,752,892			9,479,337
Tenant improvements	637,355			600,436
Equipment and furnishings	169,841			152,554
Construction in progress	234,851			303,264
	10,689,656			12,777,882
Less accumulated depreciation	(1,892,744		)	(1,709,992		)
	$	8,796,912		$	11,067,890

Depreciation expense for the years ended December 31, 2015, 2014 and 2013 was $354,977, $289,178 and $269,790, respectively.

The gain on sale or write down of assets, net for the year ended December 31, 2015 includes the gain of $311,194 on the sale of a 40% ownership interest in the PPR Portfolio (See Note 4—Investments in Unconsolidated Joint Ventures), $73,726 on the sale of Panorama Mall (See Note 14—Dispositions), $2,336 on the sale of assets and $1,807 on the sale of land offset in part by a loss of $10,633 on impairment and $182 on the write-off of development costs. The loss on impairment was due to the reduction of the estimated holding periods of Flagstaff Mall (See Note 8—Mortgage Notes Payable) and a freestanding store.

The gain on sale or write down of assets, net for the year ended December 31, 2014 includes the gain of $144,927 on the sales of Rotterdam Square, Somersville Towne Center, Lake Square Mall, South Towne Center, Camelback Colonnade and four former Meryvns' stores (See Note 14—Dispositions), $9,033 on the sale of Wilshire Boulevard (See Note 4—Investments in Unconsolidated Joint Ventures) and $1,257 on the sale of assets offset in part by a loss of $41,216 on impairment and $40,561 on the write-off of development costs. The loss on impairment was due to the reduction in the estimated holding periods of the long-lived assets of several properties including Great Northern Mall, Cascade Mall, a property adjacent to Fiesta Mall and three former Mervyn's stores sold in 2014 (See Note 14—Dispositions).

The loss on sale or write down of assets, net for the year ended December 31, 2013 includes a loss of $82,197 on impairment and $1,250 on the write-off of development costs offset in part by a gain of $5,390 on the sale of assets. The loss on impairment was due to the reduction in the estimated holding periods of the long-lived assets of Promenade at Casa Grande, Rotterdam Square, Lake Square Mall and Somersville Towne Center.