Here's an ideal itinerary for 3 days in London that includes parks and green spaces, while also allowing you to travel at a relaxed pace:

Day 1:

• Start your day with a visit to the iconic Tower Bridge. You can take a tour of the bridge or simply admire it from the outside.
• Next, head over to the Tower of London, which is just a short walk away. This historic castle has been home to many famous prisoners and is now a museum.
• After exploring the Tower of London, take a stroll along the Thames River and enjoy the views of the city.
• For lunch, head to Borough Market, one of London's most popular food markets. You'll find a wide variety of delicious food options here.
• In the afternoon, make your way to Hyde Park, one of London's largest and most beautiful parks. Take a leisurely walk around the park and enjoy the scenery.
• End your day with a visit to Kensington Palace, the former home of Princess Diana. You can take a tour of the palace or simply wander around the gardens.

Day 2:

• Start your day with a visit to St. Paul's Cathedral, one of London's most iconic landmarks. You can take a tour of the cathedral or simply admire it from the outside.
• Next, head over to the British Museum, which is home to some of the world's most important artifacts. Spend a few hours exploring the museum's vast collection.
• For lunch, head to Covent Garden, a bustling area filled with shops, restaurants, and street performers.
• In the afternoon, make your way to Regent's Park, another one of London's most beautiful parks. Take a stroll around the park and visit the famous London Zoo.
• End your day with a visit to Camden Market, a vibrant market filled with unique shops and food stalls.

Day 3:

• Start your day with a visit to the Houses of Parliament and Big Ben. You can take a tour of the Houses of Parliament or simply admire the architecture from the outside.
• Next, head over to the London Eye, one of London's most popular attractions. Take a ride on the giant Ferris wheel and enjoy the views of the city.
• For lunch, head to Greenwich Market, a charming market filled with food stalls and unique shops.
• In the afternoon, make your way to Greenwich Park, a beautiful park with stunning views of the city. Visit the Royal Observatory and stand on the Prime Meridian line.
• End your day with a visit to the Tate Modern, one of London's most famous art museums. Spend a few hours exploring the museum's vast collection of modern art.