This weekend marks 21 years since the United States faced the deadliest terrorist attack on U.S. soil. 9/11 is now a day of remembrance and reflection. A look at how the U.S. has fared 21 years later against Islamic terrorist groups is comprised of both accomplishments and skirmishes.

A recent takedown of al-Qaeda’s most prominent leader Ayman al-Zawahri is a celebrated victory for the United States. An airstrike killed al-Zawahri, the right-hand man to Osama Bin Laden responsible for planning out 9/11. Al-Zawahri was found harbored in Afghanistan after the U.S. removed its presence from the region. The State Department issued a heightened terrorism alert last month asking U.S. citizens to maintain a high level of vigilance. In the alert, officials warned of possible retaliation that could be sought by terrorist groups.

In the country’s capital of Kabul, turmoil has persisted caused by terrorist groups. A deadly attack on a Russian embassy less than a week ago killed six people. The attack has since been claimed by ISIS, according to their Telegram channel. Several other attacks this year have been claimed by ISIS including a series of blasts across Afghanistan killing at least 10 people.

This week alone, dozens of ISIS members hiding in Syria were arrested while al-Qaeda carried out an attack in Yemen killing 26 people. 21 years since 9/11, terrorist attacks are still carried out across the world, but have not been near to the extent of 9/11 where 2,977 people were killed and 25,000 others were injured.