For more than three years, the monolithic building that will house the Perot Museum of Nature and Science in Dallas has been rising alongside Woodall Rodgers Freeway, with the publicized goal of opening in 2013. Turns out they were just bit off.

Nicole Small, CEO of the Perot Museum, announced Thursday that the official opening date will be December 1 — more than a month ahead of time. The museum achieved this feat because of fundraising efforts and an aggressive construction schedule that was aided by the good weather Dallas has enjoyed of late.

Anyone anxious to be among the first to view the final product is in luck too. The museum will open up ticket sales October 2, through its website; tickets range from $10 for children to $15 for adults. The museum anticipates a strong response to its opening, so they recommend buying tickets sooner rather than later if you already had a visit on your to-do list.

Although the museum still has a lot to accomplish in the 72 days leading up to its opening, many of its features have already taken shape. The outdoor plaza in front of the building has interactive elements like oversized xylophones and a "leapfrog forest" — frog statues designed to be jumped over by children and adults.

The rooftop deck just outside the lobby will have a multitude of native Texas grasses and other plants, a project that appears about half finished at this point. The lobby, which can be freely explored without paying admission, has a fossil skeleton of a Malawisaurus that previously resided in the Fair Park museum, as well as "Dancing Water" Interactive Spheres, where models of water molecules move up and down when you walk underneath them.

The Perot Museum has already gained notice for its unique escalator, which rises on the "outside" of the building, giving visitors a nice view of downtown Dallas, and for its ambitious plans with its various exhibit halls, among other things. With this advance opening date, you can add a visit to the new Perot Museum to your Christmas list.