Work crews completed the giant waterfront Rem Koolhaas (OMA) building in Rotterdam, the Netherlands on Thursday—16 years after the project startedDe Rotterdam is slated to open early next year. Here are six facts to know.

1. Here's where Rotterdam is.

Credit: Courtesy of Google Maps

2. De Rotterdam really is a "vertical city." Check out these diagrams.

Credit: Courtesy of OMA

3. OMA's building is the biggest in the Netherlands, with 1,722,230 square feet of floor space.

Credit: Image courtesy of OMA

4. That bridge in all of the pictures is the 1996 Erasmus Bridge, designed by UNStudio's Ben van Berkel. Its tower is 456 feet tall, just shy of Koolhaas' 492 feet (Although they probably don't start on the same sea-level.) This is the bridge in 2009.

Credit: Massimo Catarinella/Wikimedia Commons


5. About 85 percent of De Rotterdam's space has been rented or sold, despite criticism that it's a large building in a city with a large amount of vacancies.

Credit: Courtesy of OMA; photography by Ossip van Duivenbode

6. It's been compared to Legos and the twin towers "resurrected in a Frankenstein muddle."

Credit: Image courtesy of OMA

Update: This post originally misspelled the name of Ben van Berkel.