Ostia Antica is an ancient seaport about one hour outside of Rome (getting there is pretty easy- just a combo metro/suburban train ride and then a short walk) and it’s also a huge site. It’s a lot greener than Pompeii, and also much less crowded. Though I imagine during the summer it would be crowded, and crazy hot! Even today, at the end of October, it was hot and sticky. There isn’t a lot of posted info throughout the site- there are some signs highlighting the biggest buildings, but not much else- so if you do go, and you want to know what each thing is, I suggest you get either a guidebook or a map. You can buy maps at the ticket office, but I decided to wander around without a map:) The ancient city was basically set up just like a grid, so even very directionally challenged me didn’t get lost!