From Wikipedia:

Sultan Omar Ali Saifuddin Mosque is a royal Islamic mosque located in Bandar Seri Begawan, the capital of the Sultanate of Brunei. The mosque is classified as one of the most spectacular mosques in the Asia Pacific and a major tourist attraction. Sultan Omar Ali Saifuddin Mosque is considered amongst the people of Brunei as the country’s major landmark.

I agree that it is most certainly a beautiful mosque, masha’allah. I received a couple of photos of the mosque in my inbox just now. Here is a picture of the interior.

I must certainly pay a visit to Brunei one day, if only just to see the mosque.