https://www.apnews.com/a7c524fcd45e4c99959970d337dbdc3c

Honestly, what's it gonna take to convince you man

Recent assaults by tactical teams on prototypes of President Donald Trump’s proposed wall with Mexico found their imposing heights should stop border crossers
Military special forces based in Florida and U.S. Customs and Border Protection special units spent three weeks trying to breach and scale the eight models in San Diego, using jackhammers, saws, torches and other tools and climbing devices,
Tubes atop some models repelled climbing devices
The findings appear to challenge what Janet Napolitano, now chancellor of the University of California, often said when she was President Barack Obama’s homeland security secretary: “You show me a 50-foot wall, and I’ll show you a 51-foot ladder.”
Topping the steel with smooth concrete surfaces helps prevent climbing.