New York has some amazing things to see – the Statue of Liberty, the Brooklyn Bridge, and many, many others
Texas has historical sights like the NASA space centre, the infamous book depository where JFK was shot, and the Alamo. You can also check out a rodeo
Brazil has the famous statue of Jesus that overlooks Rio – and the city has a host of other cultural sights of interest
New England has most of the USA's oldest historical sights
Seattle has some great museums and restaurants. And from here, take the goth teen in your life to Forks, where the Twilight novels are set.
Washington DC arguably has the higher concentration of powerful people than anywhere else on earth. The first must-see sight is the White House, which you can take a tour of – book as early as you can, turn up early on the day, expect airport style security, and don't take any bags or cameras. Political geeks will also want to see the Capitol Building and the Library of Congress – in the Capitol Grounds, you can see a somewhat random clutch of statues of US Presidents, including the obscure President Garfield and President Grant. Far more recognisable are the sights along the National Mall, including the Washington Monument and the Lincoln Memorial. At the end of the day, you can hang with the interns in at cut-price bars that have special offers on food and beer, or melt your credit card at the top restaurants where lobbyists take politicians to impress. You should also check out the Smithsonian Institute, which is a group of museums, rather than just one building – you'll be sure to find something of interest in the vast collection!
Niagra Falls' big sight is, well, the Falls. But there are numerous ways to experience this fantastic natural wonder. Go on the Maid in the Mist Boat to sail right up to the foot of the Falls. You can also walk behind the waterfall, and do a boardwalk alongside it, and ride on a ferris wheel that gives you a great view over the rapids. And you can take a helicopter ride over Niagara Falls, or ride a cable car over the whirlpool, or take an elevator to the bottom of the waterfall – as close as you can safely get, anyway. If you get bored with the Niagara Falls themselves, or inexplicably manage to exhaust the Falls-related activities, then don't worry – you can go wine tasting, take a bus tour dedicated to the doings of gangsters, or get married.
Argentina has numerous sights of note. You're likely to start of in Buenos Aires, the pulsating Argentine capital. La Boca is the main tourist district – see the brightly painted buildings, and wander the Caminito pedestrian street to find arts and crafts. The Cementerio de la Recoleta is full of enormous and ornate tombs, and the biggest is the final resting place of Eva Peron; try to resist the temptation to make "Don't cry for her, Argentina" jokes. Buenos Aires can be a rather edgy city, so be careful – and you should also see some of the rest of Argentina. The Igazu Falls in the north are one of the natural wonders of the world, and taller and far less touristy than Niagara Falls.
The most obvious thing to see in Panama is the Panama Canal, an engineering marvel. From Panama City, take a trip to the Miraflores locks and museum. Idle there to watch the enormous ships making the crossing between the Atlantic and the Pacific Panama Viejo has some fascinating ruins, while Casca Viejo has old colonial buildings. Boquete is a pretty mountain village – come here to tour a coffee plantation, take a jeep safari in the mountainous national park, and swim in the solar powered swimming pool. Panama is a great place to see rainforests, particularly as the Panama Canal allows an easy access route into the interior of the country.