The C Phrygian scale has 7 notes: C – D♭ – E♭ – F – G – A♭ – B♭. Phrygian is a minor scale with a ♭2, one fret above the root. That dark half step gives it a Spanish, heavy feel. In Indian music it is Bhairavi thaat.
Compared with the C major scale it has ♭2 (D♭ instead of D), ♭3 (E♭ instead of E), ♭6 (A♭ instead of A), ♭7 (B♭ instead of B).
The explorer above is set to C Phrygian: the whole neck is mapped, and you can zoom into any of its 7 positions, change the labels to degrees or fingers, and hear it up, down and in patterns.