Prince William has emphasized defense on all fronts during his royal tour in Kuwait. He witnessed a special demonstration of urban warfare tactics and close quarter battle techniques that the joined British and Kuwaiti troops have been training for in dealing with their enemies. During his tour, he also waged war against plastic bottles.

The British and Kuwaiti troops carried out a military exercise called Exercise Desert Warrior on William's last day in his royal visit to Kuwait. The Duke of Cambridge closely watched the demonstration as the soldiers storming a building and slamming doors during the exercise at the Sheik Salim Al-Ali National Guard Camp in the Kuwaiti desert.

The bi-annual Desert Warrior exercise involves about 120 British soldiers, who train their local counterparts on urban warfare tactics. The joint training exercises are conducted twice a year for two weeks.

William, as a former military serviceman himself, understands the importance of training like these in the security of both countries as well as cooperation and building relationships among soldiers. The Duke's visit at the National Guard Camp was particularly meaningful as military cooperation is one of the foundations of the relationship between Britain and Kuwait.

On his last day in Kuwait, Prince William shared on the Cambridges' official Instagram account a photo of him joining Sheikh Mohamed Abdullah in a traditional Kuwaiti tent in the desert outside of Kuwait City. Prince William was shown sitting on the ground. He was also seen listening to traditional Kuwaiti music, observing Kuwaitis doing some crafts, and learning more about pit cooking and falconry.

Meanwhile, during his tour, the Duke of Cambridge also visited the al Jahra Nature Reserve outside Kuwait City. In there he wages a war against single-use plastic bottles and branded these as "enemy".

He joined a team of litter pickers in cleaning up the shore of Persian Gulf mudflats with plastic bottles, discarded packaging, and carrier bags washed up by the sea. While picking up trash, William told the other pickers that he and his family are doing recycling as much as possible.

He said when they travel, they don't use plastic bottles. They only take metal bottles with them, which they can reuse.

"I hate plastic bottles now, and I look at them, and I literally think it's the enemy. You see a plastic bottle and I'm like 'eugh!' Horrible, isn't it?" he said.

After Kuwait, Prince William will be heading to Oman, where he will end his four-day tour to the Middle East at the request of the Foreign and Commonwealth Office. In Oman, William is expected to spend time with the Royal Navy. This is William's first visit to the two countries.