Photos: Shannon.Mathew (CC BY-SA 3.0) · Varun Shiv Kapur (CC BY 2.0) · Siddhartha Sarathi Basu (CC BY-SA 3.0)
The vast ruined stone fort of Ghiyasuddin Tughlaq, built in the 1320s and soon abandoned. A causeway links it to his tomb across the road.
Ghiyasuddin Tughlaq, founder of the Tughlaq dynasty, built this fortified city around 1321, and it was abandoned within a few years. Its sloping rubble walls run for kilometres, with circular bastions and 13 of the original gates still standing. Inside are the remains of the citadel and palace area, water tanks and underground passages. Just south is the sultan's red sandstone and marble tomb, which was once reached by a long arched causeway over an artificial lake.

Within 1 km of Tughlaqabad Fort.
Themed 20-acre park in Said-ul-Ajaib with sculptures, water features, flower beds and rocky terrain designed to engage all five senses.
Ticketed open-air crafts bazaar run by Delhi Tourism, with rotating stalls from every Indian state and regional food counters.
Large protected Aravalli forest on Delhi's southern edge with trails, birdlife and the blue Neeli Jheel lake in an old mining pit.
Premium Saket mall with international fashion and beauty brands, dining, an outdoor plaza and a multiplex.
Free green park beside Hauz Khas Village with a spotted-deer enclosure, rabbits, peacocks, Lodi-era tombs and walking trails.
A garden tomb from 1754 at the end of Lodhi Road, often described as the last great monumental tomb of Mughal-era Delhi.
A 90-acre city park off Lodhi Road with 15th–16th century Sayyid and Lodi tombs set among lawns and walking paths.
Theme park near Sarai Kale Khan with replicas of the Seven Wonders of the World built from scrap metal; most atmospheric when lit at night.
The ruined 14th-century citadel of Firuz Shah Tughlaq, with a 3rd-century BC Ashokan pillar. Crowds gather on Thursdays to leave wishes for djinns.
A 16th-century citadel on Mathura Road linked with Humayun and Sher Shah Suri. Excavations here show settlement going back about 3,000 years.
A 16th-century gateway from Sher Shah Suri's era on Bahadur Shah Zafar Marg, notorious as the place where three Mughal princes were shot in 1857.
Shah Jahan's red sandstone palace-fortress in Old Delhi, finished in 1648. It is a UNESCO site and the venue for the Prime Minister's Independence Day address.
Centuries-old wholesale spice, dry fruit and herb market at the western end of Chandni Chowk, often called Asia's largest spice market.
Old Hanuman temple on Baba Kharak Singh Marg, linked by legend to the Mahabharata. Unusually, its spire carries a crescent moon. It is busiest on Tuesdays and Saturdays.
Free museum at Palam Air Force Station with historic military aircraft, weapons, uniforms and photographs tracing the history of the Indian Air Force.
India's flagship museum on Janpath, covering roughly 5,000 years of art and archaeology, from the Harappan period to the decorative arts.