With the construction on the third section of the High Line underway, this may be your last chance to see the final part of the park in its undisturbed, overgrown state.

The park has given the public sneak previews of its new sections as part of Open House New York since 2009, but this year it's doubling its Rail Yards Weekends thanks to support from Japanese clothing giant UNIQLO, which has supported the maintenance and operations of the park for two years. Each visitor will get a UNIQLO shirt at the end of the tour.

Reservations are open to anyone who is 18 or older. For the first weekend, tickets are $5 and will be available at Open House New York's website on the morning of Sept. 27. The second weekend is free, though a reservation is needed and can be made through the High Line's website starting at 12 p.m. on Sept. 27.