Kerala celebrates Atham today, marking the beginning of Onam festivities. Houses are spruced up, Pookkalams or floral carpets are laid in front of homes from today, as a symbolic gesture of welcoming the legendary King Mahabali, who is believed to visit his subjects on Thiruvonam Day. The festivities culminate on the tenth day of Atham, on Thiruvonam. At Tripunithura, capital of the erstwhile state of Kochi, the colourful Athaghoshayathra or Atham procession will start within a couple of hours from now (10 am) The Kerala Assembly Speaker G Karthikeyan will inaugurate the event. The Atham procession is a throwback on the days when the Rajah of Cochin used to visit Thrikkakara Temple to take part in the Onam festival there.Meanwhile, the ten day long Onam festival at Thrikkakara Temple associated with the Onam legend, begins this evening with Kodiyettu or flag hoisting.