Wiktionary
must-see
a. unmissable n. anything unmissable, such as a film or television programme or a tourist attraction
Usage examples of "must-see".
Someone back in Tessik told me about a must-see archeological site—.
The phenomenal growth of New Age ideas over the last twenty years had put Sedona on the map of must-sees for the crystal, aura, and alien-abduction sets.