Utopia may sound like your average travel fantasy, but it's actually about some pretty deep stuff. The text investigates some heavy-hitting questions of political philosophy, some of which are very specifically about sixteenth century European politics. That doesn't mean these questions aren't applicable today—they totally are—but it can take a little more time and consideration to draw those connections. Read: it's really confusing.
This one also requires some patience. Utopia doesn't really spend a lot of time constructing a plot or story. Mostly, it's just describing very long conversations between various characters as well as, obviously, characteristics of Utopia. All this makes for an incredibly rewarding read, but you do have to stick with it.
Oh, and did we mention it was originally written in Latin? So, you know, there's that too.