Look at the Maastoren from a water taxi on the Nieuwe Maas and the building does something strange. The base is the color of wet stone, dark grey dimension stones cut to echo the basalt of the wharf below. Climb the eye upward, though, and the panels shift through 22 distinct shades of aluminum, lightening floor by floor until the top reads as silver-white against the sky. Architect Dam & Partners, working with the French firm of Odile Decq, designed the gradient as a kind of slow vertical sunrise frozen against the river. A glass extension juts from the south face. Glass elevators climb the exterior to reach the parking deck, a feature forced by the lot's tight footprint and the cost of going deep. Below the waterline, almost 500 piles drive through layers of clay into sand, anchored by a foundation plate nearly two meters thick.

Kop van Zuid is the old port district at the south end of the Erasmus Bridge, a neighborhood that spent decades being remade from harbor cranes into residential towers. The Maastoren arrived as part of that transformation, but not everyone welcomed it. Residents formed an action committee whose original name, Comite Maastoren Nee, left no doubt about their position. They objected to the height. They objected to a parking garage that would loom ten floors above ground because burying it underground had been ruled too expensive. Construction halted in September 2006, just weeks after preparations began, while objections went through the municipal committee. By November the objections were rejected. By April 2007, mayor Ivo Opstelten hammered the first pile into the ground. The lawsuit ground on in parallel, and the city won. The tower went up anyway.

The Maastoren's most celebrated feature isn't visible from the street. Beneath the building, a seasonal thermal energy storage system pumps groundwater between summer-warm and winter-cool aquifers, heating and cooling 44 floors of office space with a fraction of conventional energy use. The engineering firm Techniplan Adviseurs won the 2007 Vernufteling award for the design, the Dutch equivalent of an engineering Oscar. Inside, twelve elevators serve the 1,600 Deloitte and AKD employees who fill the tower each day. The three express cars climb at roughly 22 kilometers per hour, fast enough that ears pop on the way to the top floors. River water from the Meuse feeds the fire sprinkler system. Even the dock at the foot of the building serves a purpose: water taxis slip in and out, making the tower one of the few skyscrapers in the world where you can arrive by boat.

The plaque in the Maastoren's lobby, presented by the Council on Tall Buildings and Urban Habitat at the May 2010 opening, declares the building 164.75 meters tall and the tallest in the Netherlands. It was true for a moment. The Zalmhaven Tower in Rotterdam would eventually overtake it, dropping the Maastoren to second place on a list it briefly led. Mayor Ahmed Aboutaleb accepted a commemorative book at the ceremony, the Rotterdam Skyscraper Foundation having decided that any building this controversial deserved its own publication. Four years later, in a single transaction worth 1.1 billion euros, the American firm NorthStar bought the tower from SEB Asset Management as part of an eleven-building portfolio. The Dutch tower with the Dutch name and the Dutch architectural fingerprints became an entry on an American balance sheet, then changed hands again. The mirrored gradient kept rising over the Meuse, untroubled.