Does anyone know what this flower is?
Monarda didyma Bee Balm, a red variety; possibly 'Gardenview Scarlet'
By-the-way, Monarda, in pretty much any color variety, is extremely attractive to Bees, Butterflies and Hummingbirds. It's also a native plant.
The garden in the pic that you posted also has several other varieties of native plants that attract bees and butterflies, so possibly it was planted for that purpose.