På dansk og E 53
A danger that has no sign of its own. The subpanel underneath tells you what it is - read it.
A Triangular with a red border: something ahead needs your attention. Outside built-up areas they normally stand 150-250 m before the hazard, closer inside town.
Drawing from Wikimedia Commons, free of copyright under section 9 of the Danish copyright act. Code and name follow executive order 425 of 13 April 2023 on road marking. Study material, not the legal text.