During my trip to Sri Lanka I had a six hour layover in Abu Dhabi. I wanted to spend my time well so decided to visit the Sheik Zayed Grand Mosque. I would absolutely recommend doing this as it is one of the most beautiful mosques in the world and you can do this easily when having a layover.
We took bus A1 into the city and switched buses in the city. This will only cost you a few euros and it will take you 30 minutes to get to the mosque. We arrived at the mosque before it opened (9AM), so we had to wait outside. We tried to find shade, as it was already over 40 degrees Celsius at 8AM. The mosque is open every day from 9AM to 10 PM, except for Friday mornings. There is no entrance fee, which makes this a perfect budget visit.
After searching for some time, we found the entrance to the mosque. I wore long trousers and brought a scarf to put over my hair, to comply with the dress code.
The Sheik Zayed Grand Mosque is absolutely breathtaking! I think everybody that loves traveling has seen pictures of the exteriors, but I loved the interiors as much as the exteriors. There is a beautiful carpet inside the mosque, the chandeliers were super impressive. As a non-Muslim I loved being able to visit the interior of a mosque, as this is not allowed in each country (Morocco for example). So this is a unique chance on your layover.
Because of the high temperatures I became super sweaty and we still had to fly from Abu Dhabi to Colombo (4,5 hours). I brought a clean shirt and deodorant in my hand luggage, but would also recommend bringing a washcloth and towel when you undertake this activity.
In 2017 the Louvre opened in Abu Dhabi. I will certainly want to do this on a next layover in Abu Dhabi. I love architecture and art museums, so this seems right up my alley. Who knows when I will be able to realize this visit!