The architects perfected the plan in 1912. At the same time the actual work of preparing the site was completed with the filling of the tide-land portions by hydraulic dredgers and the removal of the standing buildings. In the same year the department chiefs were named and began their work. John McLaren, for many years Superintendent of Golden Gate Park, was put in charge of the landscape engineering; W. D'A. Ryan was chosen to plan the illumination, and Jules Guerin and K. T. F. Bitter were placed at the heads of the departments of color and sculpture. With these details behind, the ground-breaking for Machinery Palace in January, 1913, marked the beginning of the final stage. In the two years that remained it was necessary only to carry out the plans already perfected. No other exposition has been so forehanded. When the gates opened on February 20, 1915, to remain open till December 4, the Exposition was practically complete. Some of the exhibitors had not finished their installation; some of the foreign nations were not ready, but the Exposition had kept a promise made two years before to have its own work done on time. This achievement was quite unprecedented. It is the more remarkable in that the record was made by a city which had been almost annihilated by fire a few years before. The entire cost of the Exposition, exclusive of the value of exhibits, is estimated by the Controller at $50,000,000. This total is made up of $20,000,000 spent by San Francisco and California, $10,000,000 laid out in state and foreign buildings and displays, $10,000,000 by private exhibitors, and $10,000,000 by the one hundred concessionaires on the Joy Zone. San Francisco contributed $12,500,000, the State of California $5,000,000, and its fifty-eight counties, $2,500,000. The amounts expended by foreign nations range from $1,700,000 by Argentina to sums as low as $100,000. The State of New York spent nearly $1,000,000. II. Ground Plan and Landscape Gardening The Exposition a product of co-operation of the arts--The landscape made part of the scheme--Block grouping of palaces and courts--Plan of the buildings--McLaren's wonders in gardening--Succession of flowers throughout the Exposition--Changes overnight--Unique wall of living green. The artistic quality which distinguishes this Exposition above all others in America or Europe rests on two outstanding facts: the substantial unity of its architectural scheme, and its harmony of color, keyed to Nature's coloring of the landscape in which it is placed. The site furnished the clue to the plan; co-operation made possible the great success with which it has been worked out.