Didim is an Aegean beach town with one ancient sight big enough to pull it above the normal resort-strip crowd. The modern town sprawls around Altinkum's sand and promenade, but a short walk inland brings you to the Temple of Apollo at Didyma, one of the great unfinished monuments of Ionian antiquity.
That contrast is the point of Didim. You can spend the morning among column bases, oracle chambers, and stone corridors that still feel oversized, then swim in the afternoon without changing towns. The beach side is plain holiday infrastructure, with sun beds, family restaurants, and summer crowds, but the water is good and the pace is easy.
Didim also works as a practical southern base for the classical triangle of Didyma, Miletus, and Priene. If you only want a polished resort, there are prettier places on the Turkish coast. If you like mixing archaeology with a swim and a cheap dinner by the sea, Didim earns its day.