Colosseum
It's the biggest, oldest structure most children will ever stand inside.
Finished around 80 AD and still mostly standing, the Colosseum lets you look down into the underground passages where gladiators and animals once waited. Book timed tickets well ahead and go at opening, before the queues and heat build; there's almost no shade inside, so bring water and hats. A combined ticket usually includes the Roman Forum next door — with young kids, keep it optional and short.
Photo: Steven Guillemet
