I've visited the 9/11 Memorial a couple of times so skipped it on this trip; One World Trade Center (ie Freedom Tower) is still jaw-dropping as the tallest building in the Western Hemisphere (the same architect designed Willis Tower and Burj Khalifa)
The cholla cactus has been nicknamed the teddy bear cactus due to it’s friendly look but do not be fooled!; also known as the jumping cactus, the chollas have a way of snagging feet and legs with thorns that are difficult to extract