Hekatomnos Anıt Mezarı ve Kutsal Alanı shows up as one pick among the activity venues in Milas. The category runs wide — anything from a hands-on workshop to a full-day outing counts as "activity" — so the real question isn't which venue wins some imaginary contest, it's whether this particular one matches what you're in the mood for today. Worth a look before you rule it out.