Parliament House is the Renzo Piano building just inside Valletta's City Gate, completed in 2015 as part of the city's modern entrance ensemble. Its two raised limestone blocks are deliberately unlike the surrounding baroque streets, which is exactly why locals still argue about it.
Public access is limited, so treat it as an architecture stop rather than a museum. It is easiest to see while entering the city, beside City Gate and the open-air Pjazza Teatru Rjal.