OWASP Juice Shop
Probably the most modern and sophisticated insecure web application
... to exploit the underlying vulnerabilities. The hacking progress is tracked on a scoreboard. Finding this scoreboard is actually one of the (easy) challenges! Apart from the hacker and awareness training use case, pentesting proxies or security scanners can use Juice Shop as a “guinea pig”-application to check how well their tools cope with JavaScript-heavy application frontends and REST APIs.