What do you think the most peaceful, relaxing drug is?

Prescription or recreational, or a plant or herbs like Kava and Marijuana? Legal or illegal. I want to know which drug you think would be the best to just lay back and chill, maybe play some slow or trippy music, and just feel extremely euphoric, maybe go on a spiritual out of body adventure! What drug do you think does this the best? What's your opinion? And if you don't know, just post your favorite drug, legal or illegal, prescription or not.