Igrek, Warsaw, Multifamily residential building in Downtown, Warsaw, Poland.

Igrek is a residential block at 55 Emilii Plater Street in Warsaw's Śródmieście district, built on a Y-shaped plan meant to echo the UNESCO headquarters in Paris. It forms part of the Mariańska housing estate, designed by Hanna Lewicka and Wojciech Piotrowski and built between 1961 and 1967. Completed in 1964, it was designed for 920 residents.

The building was constructed in 1964 and was among the first large residential complexes of its kind in Warsaw. It marked the beginning of a new era in how the city approached modern residential development.

Locals call the block both Igrek, Polish for the letter Y, and Wiatrak, windmill, after its three-winged plan. The Y layout was modelled on the UNESCO headquarters in Paris. The building forms part of the Mariańska estate, built 1961–1967 to designs by Hanna Lewicka and Wojciech Piotrowski.

Igrek stands at 55 Emilii Plater Street, within the Mariańska estate bounded by Emilii Plater, Twarda and Świętokrzyska streets in Śródmieście. The building is a private residential block, so visitors view the Y-shaped façade from the street and courtyard side rather than entering the stairwells.

Architects Hanna Lewicka and Wojciech Piotrowski drew inspiration from the UNESCO Headquarters in Paris when designing this building, adapting the concept for residential use. This connection to a world-known structure makes it an unexpected detail in Warsaw's modern architectural history.