On April 9, 1965, the world¡¯s largest air-conditioned playground ¨C Houston Sky Center ¨C opened today. President Johnson participated in a baseball match between the New York Yankees and the Houston Sky Team, the first indoor baseball match. The center of the sky was built on a land that used to be a pastoral farm, with a height of 208 feet and capacity for 50,000 spectators, and the disadvantage was the transparent plastic plate on the round roof that made the outer hands unseen the ball. The orange yellow ball is being tested, but it seems necessary to replace the plastic plate.