Delhi, Delhi (National Capital Territory)

Delhi is India's capital and one of the oldest continuously inhabited cities in the world. It spreads across roughly 1,500 square kilometres on the banks of the Yamuna in northern India, home to well over 30 million people in the wider National Capital Region.

The city is really several cities layered on top of each other. Successive rulers — Tomaras, the Delhi Sultanate, the Mughals, the British — each built their own capital here, and the remains of all of them survive. You can stand at the 12th-century Qutub Minar in the morning, walk through 17th-century Mughal Old Delhi at midday, and end the afternoon on the wide colonial avenues of Lutyens' New Delhi.

Three UNESCO World Heritage Sites sit within the city limits: the Qutub Minar complex, Humayun's Tomb and the Red Fort. Alongside them, Delhi is a working capital — the seat of government, a major business centre, and the country's principal international gateway.

Delhi is the most efficient way to understand India's history, because so much of it is stacked in one place.

Nowhere else can you trace nearly a thousand years of architecture on foot in a single day — Slave Dynasty, Sultanate, Mughal, colonial and modern, each with monuments still standing and largely intact. Three World Heritage Sites, dozens of major monuments, and some of the country's best museums.

It is also India's food capital in a way few dispute. Old Delhi's street food, Punjabi cooking, Mughlai kitchens that have run for generations, and the widest range of regional Indian cuisine anywhere in the country, since people from every state live here.

Practically, Delhi is the gateway to northern India. The Golden Triangle with Agra and Jaipur starts here, as do routes to Rajasthan, the Himalayas, Amritsar and Varanasi. Its metro is the best urban transport system in India, which makes a city this large genuinely navigable.