Fixed Assets

As of December 31, 2017 and 2016, Fixed Assets consisted of the following (in thousands of dollars):



December 31,	2017			2016
Land	$	92,591		$	92,155
Buildings and building improvements	235,222			230,803
Leasehold improvements	84,504			72,969
Computer hardware and software	77,179			74,744
Furniture, fixtures and equipment	81,031			76,829
Construction in progress	9,492			3,621
Other	1,767			5,257
Sub-total	581,786			556,378
Less: Accumulated depreciation and amortization	(229,751		)	(209,196		)
Total Fixed Assets, net	$	352,035		$	347,182

We recently completed a review of our New York real estate holdings and concluded that we will continue to occupy our headquarters at 1334 York Avenue in New York for the foreseeable future. In September 2017, we decided to undertake an enhancement program, beginning in June 2018, to create new state-of-the art galleries, as well as new public and client exhibition spaces. As a result of this enhancement program, certain building improvements and other fixed assets will be removed from service before the end of their originally estimated useful lives, resulting in accelerated depreciation expense of $1.9 million recognized in the fourth quarter of 2017.

For the years ended December 31, 2017, 2016, and 2015, Depreciation and Amortization related to Fixed Assets was $22.1 million, $19.9 million, and $19.5 million, respectively.