Qutub Minar, located in Delhi, India, is a UNESCO World Heritage Site and one of the most iconic monuments in the country. It is a towering example of Indo-Islamic architecture and stands at a height of 73 meters (240 feet), making it one of the tallest brick minarets in the world. The construction of the Qutub Minar was started by Qutb-ud-din Aibak, the founder of the Delhi Sultanate, in 1193 AD, and was completed by his successor, Iltutmish. The minaret is made of red sandstone and marble, with intricate carvings and verses from the Quran inscribed on its walls. The tower is divided into five distinct stories, each marked by a projecting balcony.

Humayun's Tomb, located in Delhi, India, is a magnificent mausoleum and a UNESCO World Heritage Site. It was built in the 16th century and is considered to be the precursor of the Taj Mahal due to its architectural significance. The tomb was commissioned by Empress Bega Begum, the widow of Emperor Humayun, and was designed by Mirak Mirza Ghiyas, a Persian architect. The tomb is built primarily of red sandstone, with white marble inlays and intricate carvings. It is set in a large Charbagh (fourfold) garden, typical of Persian and Mughal style, with pathways and water channels dividing the garden into four squares.

Jama Masjid, located in the heart of Old Delhi, is one of the largest and most magnificent mosques in India. Built by the Mughal emperor Shah Jahan between 1644 and 1656, it is constructed of red sandstone and white marble, showcasing the architectural grandeur of Mughal design. The mosque's courtyard can accommodate up to 25,000 worshippers, and its main prayer hall is adorned with intricate marble carvings and inscriptions from the Quran. The mosque also houses several relics, including an ancient copy of the Quran written on deer skin.

Chandni Chowk is one of the oldest and busiest markets in Old Delhi, India. It was built in the 17th century by the Mughal emperor Shah Jahan and designed by his daughter Jahanara Begum. The name "Chandni Chowk" translates to "Moonlight Square" or "Moonlight Market," referring to the market's location opposite the Red Fort, where moonlight would reflect off its white marble. Chandni Chowk is renowned for its vibrant street markets that offer a wide variety of goods, including textiles, electronics, jewelry, spices, and street food. The area is also famous for its narrow lanes, bustling atmosphere, and historical landmarks.