Delhi's sprawling suburbs keep expanding southward, impervious of the remnants of the ancient cities they surround. Die-hard historians may feel impelled to visit the ruins of Siri (the second city), Tughlaqabad (the third), and Jahanpanah (the fourth), but the principal attraction here is the Qutb Complex, built in the area that comprised the first city of Delhi. Located in Mehrauli Archaeological Park, it has a number of historic sites centered around the Dargah of Qutb Sahib, as well as a number of cafes and boutiques frequented by Delhi's well-heeled.
Nearby is Hauz Khas on the Delhi-Mehrauli road. Once a village, Haus Khas is now a gentrified upmarket suburb known more for its glossy boutiques and restaurants than for its 14th-century reservoir and ruins, including the tomb of Feroze Shah Tughlaq (Rs 100). If you happen to have a train fetish, you shouldn't miss The National Railway Museum (tel. 011/2688-1816; Rs 10; Tues-Sun 9:30am-7:30pm, closes 5pm in winter), said to be one of the world's most impressive -- hardly surprising given India's huge network. You can ogle all kinds of saloon cars and locomotives, and even swoon at model trains and railway maps of yore. It is situated southwest of Lodi Gardens, in Chanakyapuri.
If you've traveled this far south, head a little east to look at the Bahá'i House of Worship, or "Lotus Temple," where 27 huge and beautiful marble "petals" create the lotus-shaped dome. Often likened to a miniversion of the Sydney Opera House, it's a beautiful contemporary temple, and invites people of all faiths for worship. It's sometimes described as a modern counterpoint to the Taj, but this is an injustice to the Taj, as the Lotus Temple lacks any detailing and has a drab interior (Kalkaji; tel. 011/2644-4029; Apr-Oct Tues-Sun 9am-7pm, Nov-Mar Tues-Sun 9:30am-5:30pm).
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.