Willis Tower is a 110 story high rise in Chicago, Illinois, United States of America. This high rise is 1450 foot (442 m) high. This tallest high rise of USA has 104 lifts with 16 double decker lifts. Its development was begun in 1970, and it was finished in 1973. After its consummation in 1973 ,this high rise was first named as Sears Tower yet in 2009 its name was changed into Willis Tower. It was the most elevated building on the planet since its creation. The pinnacle is as yet holding the record of the tallest building in the United States and the fifth tallest unattached structure on the planet. The arranging and development of the taking off Sears Tower was made in 1969 when the proprietor, Sears, Roebuck and Co., the biggest retailer on the planet chose to combine their roughly 350,000 workers in a single 3 million square feet building as they are scattered all through Chicago territory. The celebrated counseling draftsman, Skidmore, Owings and Merrill was appointed to develop one of the biggest workplaces building on the planet. The outline is very amazing in light of the fact that it is made out of 9 square tubes – each basically a different building – and all will ascend and end at the 50th floor, the 7 tubes will rise and end at the 66th floor, the 5 tubes will go up and end at 90th floor lastly the 2 remaining tubes will proceed to the 110th floor. As the tallest building in Chicago numerous TV slots were fighting to get the rights to mount their radio wires. In February 1982 one TV channel introduced their recieving wires expanding the stature to 1,707 feet (520 m) . In June 2000 another radio wires was mounted and additionally raising the tallness to 1,730 feet (527 m.). In giving extra courtesies particularly to the travelers the Sears Tower has given the Skydeck perception deck at 103rd story. This was opened in June 1974 and it takes just 60 seconds to come to the Skydeck. This is a standout amongst the most well known among the visitors where they can encountered the influencing of the building amid blustery period and have a decent perspective of the fields of Illinois, Lake Michigan, Wisconsin and Indiana on a sunny morning. In January 2009, with the eager acknowledgment by the voyagers, the Sears Tower introduced the glass galleries with an overhung of 4 feet in the Skydeck where one can see through the floor to the road down beneath. The Skydeck has a normal guest of 1.3 million vacationers yearly.