===Critical Hits & Critical Misses
Rolling 1 or 20 PHB p194 [–] Sometimes fate blesses or curses a combatant, causing the novice to hit and the veteran to miss.
If the d20 roll for an attack is a 20, the attack hits regardless of any modifiers or the target's AC. This is called a critical hit, which is explained later in this chapter.
If the d20 roll for an attack is a 1, the attack misses regardless of any modifiers or the target's AC. Unseen Attackers and Targets PHB p194 [–] Combatants often try to escape their foes' notice by hiding, casting the invisibility spell, or lurking in darkness.