My son is 16 months old. He goes to bed at 6:30 or 7 every night. (Mostly 6:30).
He wakes up, like clockwork, at 6:30 am.
He takes a 2-3 hour nap every day beginning at 10am.
He's a flexible kid, and with some care we can keep him up late. If we are out, if we are at a restaurant longer than expected, if it is a family party, if we are on a flight etc... but no matter WHAT he will wake up at 6:30 am. Even when we travel to and from England - he's just got this weeeeeird body clock that find 6:30 am and sticks to it.