On Katy Perrys 2013 album,Prism, theres a song called International Smile.

That feel-good champion is hard to find onWitness, Perrys eagerly anticipated follow-up.

Instead the 32-year-old is mostly reflective, anxious and fired up.

And can you really blame her?

In the four years sincePrisms release, the world has profoundly changed, including for Perry.

Proud girl-power moments like those course throughout much ofWitness.

Theres also a curious detour into gospel territory on the uplifting Pendulum.

In fact, many of these songs are written in sad-sounding minor keys as opposed to cheery major ones.

Its a smart trick.

Still, this is a Katy Perry record, so she wisely serves up a few sugar rushes.

), musically its a delicious slab of Eurodisco.

Best TracksDeja VuA chronicle of a doomed relationship, with a groove thats lighter than air.

Swish SwishPerrys sassy kiss-off to a calculated phony, featuring a fiery verse from Nicki Minaj.