You have escaped your captors and reached The Internet™.
Next steps:
Captive portals are usually janky software, so it's better to access this site using a private browser window to avoid weird behavior due to cookies.
Captive portals on open public WiFis can be finicky and trying to access a secure https:// URL before passing them leads to problems where websites ostensibly hang or pop up scary security warnings.
The most reliable way to trigger them is to access an unencrypted website starting with http://. However most websites on the Internet (fortunately) also have an https:// endpoint (this includes fan-favorites https://example.com/ and https://captive.apple.com/) and modern browsers -- somewhat nondeterministically -- try to be smart about it and redirect automatically to the more secure version.
nohttps.lol -- as the name suggests -- will never have an https:// endpoint. You can add it to your bookmarks and use it to reliably trigger captive portals while roaming the world.
Made by Hynek, because he likes to travel, but can't remember the hostnames of the trillion other sites that do the same thing. Hosted by Variomedia AG -- your best source for rock-solid hosting and weird domain names.