New York City's new modular apartment building is the tallest in the world - take a look inside

When a building is modular, the majority of its construction happens offsite. The finished parts (rooms, hallways, terraces) are then pre-assembled and delivered to the site, allowing for a quicker construction. Modular design also helps developers save money, since factory workers generally make lower wages than those on construction sites.

461 Dean, a 32-story apartment complex in Brooklyn, is the newest residential tower in New York City to feature modular construction. It's now considered the tallest modular tower in the world. The apartments' pre-fabricated rooms fit and lock together like a puzzle pieces. The modules were placed by cranes to create the building.

Its developer, Forest City Ratner Companies, built 90% of 461 Dean in its factory at the Brooklyn Navy Yard. That allowed them to save 20% on construction costs, Forest City's VP of residential development, Adam Greene, tells Business Insider.

The complex's construction process has been rocky, however. Due to disagreements and subsequent lawsuits between Forest City and construction partner Skanska, construction (which started in late 2013) was delayed for months. According to Curbed, reports of water leaks at 461 Dean have also persisted. However, the building nevertheless topped out in May and is expected to be complete by the end of the year.

461 Dean started leasing on November 15, and the first tenants will move in by the beginning of December. Studios start at $2,450 per month, with one-bedrooms from $3,125 and two-bedrooms from $4,750.

Take a look inside.