Chennai's soil is mostly clay, shale and sandstone. Sandy areas are found along the river banks and coasts, such as Thiruvanmiyur, Adyar, Kottivakkam, Santhome, George Town, Tondiarpet and the rest of coastal Chennai. Here rainwater runoff percolates quickly through the soil. Clay underlies most of the city including T. Nagar, West Mambalam, Anna Nagar, Villivakkam, Perambur and Virugambakkam. Areas of hard rock include Guindy, Perungudi, Velachery, Adambakkam and a part of Saidapet. Chennai is divided into four broad regions: North, Central, South and West. North Chennai is primarily an industrial area. Central Chennai is the commercial heart of the city and includes an important business district, Parry's Corner. South Chennai and West Chennai, previously mostly residential, are fast becoming commercial, home to a growing number of information technology firms, financial companies and call centres. The city is expanding quickly along the Old Mahabalipuram Road and the Grand Southern Trunk Road (GST Road) in the south and towards Ambattur, Koyambedu and Sriperumbdur in the west.Chennai is one of the few cities in the world that accommodates a national park, the Guindy National Park, within its limits.
Chennai is a major centre for music, art and culture in India. The city is known for its classical dance shows and Hindu temples. Every December, Chennai holds a five-week long Music Season celebrating the 1927 opening of the Madras Music Academy. It features performances (kutcheries)
Kochi was the centre of Indian spice trade for many centuries, and was known to the Yavanas (Greeks) as well as Romans, Jews, Arabs, and Chinese since ancient times. Kochi rose to significance as a trading centre after the port at Kodungallur (Cranganore)
As a result of successive waves of migration over the course of several centuries, the population of the city is a mix of people from all parts of Kerala and most of India. The pan-Indian nature is highlighted by the substantial presence of various ethnic communities from different parts of the country.
Kochi has a diverse, multicultural, and secular community consisting of Malayalies, Konkanies, Gujarathies, Bengalies, Punjabies, Marathies, Tamilians, Biharies and a few families of Jews among other denominations, all living in peaceful co-existence. The city once had a large Jewish community, known as the Malabar Yehuden—and now increasingly as Cochin Jews—that figured prominently in Kochi's business and economic strata. The Syro-Malabar Church, one of the 22 sui iuris Eastern Catholic Churches, has its seat at Ernakulam. Prominent places of Christian worship include the St. Mary's Cathedral and the St. Antony's Shrine at Kaloor. Appropriate to its multi-ethnic composition, Kochi celebrates traditional Kerala festivals like Onam and Vishu along with North Indian Hindu festivals like Holi and Diwali with great fervour. Christian and Islamic festivals like Christmas, Easter, Eid ul-Fitr and Milad-e-sherif are also celebrated. A merry making fest called the Cochin Carnival is celebrated at Fort Kochi during the last ten days of December.
The residents of Kochi are known as Kochiites; they are an important part of the South Indian culture. However, the city's culture is rapidly evolving with Kochiites generally becoming more cosmopolitan in their outlook.The people are also increasingly fashion-conscious, often deviating from the traditional Kerala wear to western clothing.
Kochiites generally partake of Keralite cuisine, which is generally characterised by an abundance of coconut and spices. Other South Indian cuisines, as well as Chinese and North Indian cuisines are popular. Fast food culture is also very prominent.