Final answer:
The speaker in 'Sailing to Byzantium' wants to go to Byzantium to escape the decay of the physical world and achieve spiritual immortality through his art.
Step-by-step explanation:
The speaker in 'Sailing to Byzantium' wants to go to Byzantium because it represents a timeless and eternal place where he can escape the decay and impermanence of the physical world. The speaker seeks spiritual immortality and seeks to leave a lasting legacy through his art. He believes that in Byzantium, he can become like the golden mosaics and statues found in the city, permanent and revered.