Explore the Islamic Cairo district on your fourth day. Visit the historic mosques such as the Sultan Hassan Mosque and the Al-Rifa'i Mosque, known for their stunning architecture and intricate designs. Take a stroll through the bustling streets of Khan El Khalili once again, and indulge in some shopping for traditional crafts and spices. In the afternoon, head to Al-Azhar Park, a beautiful green oasis in the heart of Cairo. Enjoy a picnic or relax in the serene surroundings while admiring the panoramic views of the city. End your day with a delightful dinner at Abou El Sid, savoring the flavors of Egyptian cuisine.