Brighton Pier has a long history and has been Grade II listed since 1971. You can’t visit Brighton without taking a stroll along the pier, and taking a break in a deckchair (weather permitting!) There are good views back to shore and possible views of the Isle of Wight (try going to the top of the Helter Skelter).
The Palace of Fun and The Dome provide a myriad of arcade games. Even if this is not your idea of fun, do venture inside and look up at the beautiful ceilings.
And take a moment to enjoy the beautiful stained glass windows.