Abu Dhabi: the Grand Mosque at dusk, and the Louvre's dome

The Sheikh Zayed Grand Mosque is free, with a dress code (abayas are lent to women) and online registration; arrive an hour before sunset to see the white marble turn gold and the lights come on. The Louvre Abu Dhabi's rain-of-light dome is worth the ticket even for the building alone; go late afternoon and stay for the evening. The bus from Dubai takes about two hours and is cheap; the Al Ain oasis and camel market are a further day.