London

Here's an ideal itinerary for 3 days in London, with a day trip to Cornwall:

Day 1:

• Start your day with a visit to the iconic Tower of London. This historic castle has served as a royal palace, prison, and even a zoo over the centuries.
• After exploring the Tower, take a stroll along the Thames River to see some of London's most famous landmarks, including the London Eye, Big Ben, and the Houses of Parliament.
• For lunch, head to Borough Market, one of London's oldest and largest food markets. You'll find everything from fresh produce to artisanal cheeses and baked goods.
• In the afternoon, visit the British Museum, which houses an incredible collection of artifacts from around the world, including the Rosetta Stone and the Elgin Marbles.
• End your day with a show in London's West End theater district. There are dozens of shows to choose from, ranging from classic musicals to cutting-edge plays.

Day 2:

• Start your day with a visit to St. Paul's Cathedral, one of London's most iconic landmarks. Climb to the top of the dome for stunning views of the city.
• Next, head to the Tate Modern, a world-renowned museum of modern and contemporary art. The museum is housed in a former power station and features works by artists like Picasso, Warhol, and Hockney.
• For lunch, head to Brick Lane, a vibrant neighborhood known for its street art and diverse food scene. You'll find everything from Indian curries to Jewish bagels here.
• In the afternoon, explore the trendy neighborhoods of Shoreditch and Hoxton, where you'll find independent boutiques, vintage shops, and hip cafes.
• End your day with a drink at one of London's many rooftop bars, such as the Sky Garden or the Queen of Hoxton.

Day 3:

• Take a day trip to Cornwall, a beautiful region on the southwest coast of England. You can take a train from London to Penzance, a charming seaside town with a rich history and stunning views of the ocean.
• From Penzance, you can explore the nearby fishing villages of St. Ives and Mousehole, both of which are known for their picturesque harbors and quaint cottages.
• For lunch, try some of Cornwall's famous seafood, such as fish and chips or a Cornish pasty (a savory pastry filled with meat and vegetables).
• In the afternoon, visit the Minack Theatre, an open-air theater perched on the cliffs above the sea. The theater hosts performances throughout the summer months and offers breathtaking views of the coastline.
• End your day with a walk along the South West Coast Path, a scenic trail that winds along the cliffs and beaches of Cornwall.

I hope this itinerary gives you some inspiration for your trip to London and Cornwall!