The London County Council continued the policy of the Metropolitan Board of Works, and by the year 1904-5 it had carried out, or was in process of carrying out, improvements at an estimated gross cost of over £11,000,000,[193] the greatest and most costly of all being the new thoroughfare--Kingsway and Aldwych--connecting Holborn with the Strand, which swept away some of the most notorious and worst slums in London. In addition to these, many local improvements have been carried out by the "City" and by the Vestries and District Boards, and later by the Borough Councils. These were estimated to cost about £1,800,000. The total work accomplished, therefore, has been very considerable, but the cost has been huge; amounting in the whole to about £27,000,000. Of greater value to the health of the people has been the increase of the number of parks and open spaces in London, not merely in preventing land being built over, but in the opportunities afforded the people, and especially the younger portion of them, for exercise. Here considerable acquisitions have been made since the time of the Metropolitan Board of Works. Immediately after the creation of the London County Council two generous gifts were made to the citizens of London--Waterlow Park of 30 acres and Myatt's Fields--and the Council had acquired Hackney Marsh, with 337 acres; Brockwell Park, with 127 acres; and Avery Hill, 84 acres; and some distance from London, 803 acres of Hainault Forest. In addition to these several small pieces of ground were acquired and thrown open as public gardens and recreation grounds. The "City" had also acquired, outside the County of London, Epping Forest, about 5,560 acres in extent, Burnham Beeches, 375 acres; Coulsdon Common, 347 acres; and a few small open spaces in the "City" itself. And many acquisitions had been made by the Vestries and District Boards, and, since their supersession, by the Borough Councils. Purity of air was another of the important elements of a satisfactory health condition. Once that the Thames had ceased to be the main sewer of London, and once that the hundreds of thousands of cesspools were filled in and abolished, the most persistent and fruitful and worst of the causes of the impurity and unwholesomeness of the atmosphere were removed. Gradually too, but only too slowly--a slowness resulting in widespread loss of health and life--were the noxious trades in London made amenable to the law, and somewhat less noxious to those living in their immediate neighbourhood; this, too, without that ruin to trade and manufactures which was always predicted when any effort was made to prevent the prevalence of intolerable nuisances.