A view of the SlotZilla zipline under construction in downtown Las Vegas Monday, Sept. 23, 2013. There will be a lower zipline and an upper "zoomline." The zoomline will span the length of the Fremont Street Experience canopy. The take-off tower is an 128-foot tall, 12-story slot machine-themed platform. The $11.5 million attraction is expected to open later this year.