One of the top places to see in Delhi, the Purana Qila or the Old Fort has a lot in store for its visitors. It was built under Sher Shah Suri and is considered to be the capital of the Pandavas. Stretched across two kilometers in length, the huge red sandstone ramparts of the fort emphasize on the historical valor and aura of the times the fort must have witnessed. https://www.mapsofindia.com/my-india/travel/the-magnificent-purana-qila-or-the-old-fort

This great mosque of Old Delhi is the largest in India, with a courtyard capable of holding 25,000 devotees. It was begun in 1644 and ended up being the final architectural extravagance of Shah Jahan, the Mughal emperor who built the Taj Mahal and the Red Fort. The highly decorative mosque has three great gates, four towers and two 40 m-high minarets constructed of strips of red sandstone and white marble. Travellers can hire robes at the northern gate. This may be the only time you get to dress like a local without feeling like an outsider so make the most of it. http://www.delhitourism.gov.in/delhitourism/tourist_place/jama_masjid.jsp