Parts of the wall are natural, as the masonry, which includes stone, brick, wood and earth, with mountain ridges and rivers. While parts of the wall were built as early as the 7th century B.C., the majority of what still stands today, in some form, was built in the Ming Dynasty. The wall was built to defend against nomadic people to the north, but it also helped various administrations control trade and immigration.

2. The Inca were famous for building an epic series of roads that cross the mountains, deserts and coastlines of South America. But perhaps their most important architectural achievement was this building , a citadel that sits about 8,000 feet in elevation in the Andes of southern Peru. Due to its remoteness, the site had limited European visitors, and was only rediscovered in the 19th century.

Parts of the Platform of the Eagles and Jaguars, the Skull Platform and the Temple of the Warriors show significant influence from the Toltec of Tula in central Mexico.

In any case, the city has been partly preserved and rebuilt. This includes the Temple of Kukulcán, which today boasts an optical effect every year at spring equinox. A feathered serpent descends from the stairs of the pyramid.

5. The work on the towering statue symbol of Rio de Janeiro on was completed in 1931, making it the most recently built of the new seven wonders.

A French-Polish sculptor and Brazilian and French engineers created the statue. It stands nearly 100 feet tall on the top of a 26-foot pedestal, which itself sits on top of the Corcovado mountain in a national park in the city.

The building was such a masterpiece that Jahan and Mahal’s son, Aurangzeb, buried him there alongside his mother when he died. As it stands, Jahan’s sarcophagus sits off to the side of his wife’s, nearly the only exception to the incredible symmetry of the tomb.

TRAVEL - TRIP - JOURNEY - TOUR - VOYAGE

Meaning and use of the words 'trip', 'travel', 'journey', 'tour', and 'voyage'.

The explanation below should help clarify the meaning and use of vocabulary related to travel.

TRAVELThe word 'travel' is used to talk about going from one place to another.
It can be a verb, a noun or an adjective :

• Verb : Paul travels a lot in his job.

• Noun :   Travel nowadays is faster than before.

• Adjective : There is a travel agency beside the bank.

TRIP The word trip is used to talk about a short journey somewhere for a purpose, business or pleasure.

• For our wedding anniversary, we went on a trip to Venice.

• My boss is often away on business trips.

• During our holiday we took a boat trip to the islands.

JOURNEYA journey is the distance covered when travelling from one place to another.
'Journey' can refer to a long distance or a short regular one.

• The journey was long and tiring. It took us 5 hours to get there.

• Did you have a good journey? Yes, it was quite pleasant.

• How long is your journey to work? Just about 20 minutes.

TOURA tour is a journey during which several places are visited, especially on a holiday.
'Tour' can be a noun or a verb.

• Noun : We went on a tour of Italy.

• Verb :  We toured the north of India.

VOYAGEA voyage is a long journey by sea or in space.

• Before the 20th century, long sea voyages were common.

• A spacecraft will take you on a voyage through space.

We use must not to talk about what is not permitted. It is common on public signs and notices informing people of rules and laws.

Visitors must not park in the staff car park.
Baggage must not be left unattended.
Guests must not make noise after 10 p.m.

We use mustn't particularly when the prohibition comes from the speaker.

(Parent to child) You mustn't say things like that to your sister.
(Teacher to student) You mustn't be late to class.
I mustn't let that happen again.

Obligation

We use have to and must to express obligation. There is a slight difference between the way we use them.

have to

Have to shows us that the obligation comes from outside the speaker. 

We have to wear a uniform when we're working in reception.
(Student to teacher) When do we have to hand in our homework?
Al has to work tomorrow so he can't come.

We sometimes call this 'external obligation'.

must

Must expresses a strong obligation or necessity. It often shows us that the obligation comes from the speaker (or the authority that wrote the sentence). 

I must phone my dad. It's his birthday today.
(Teacher to student) You must hand in your homework on Tuesday or you will lose ten per cent of your mark.
(Sign on a plane) Seat belts must be worn by all passengers.

Note that we don't use must to express obligation in the past. We use have to instead.

I had to pay £85 to renew my passport last week.

No obligation

don't have to

We use don’t have to to show that there is no obligation. You can do something if you want to but it's not compulsory.

You don't have to wear a tie in our office but some people like to dress more formally.
You don't have to go to the bank to do a transfer. You can do it online.
You don't have to come with me, honestly. I'll be fine!

1. The Great Wall of China is the longest man-made structure ever built. This impressive wall took over 200 years to build.

2. Believe it or not, that impressive ancient city that you saw in Indiana Jones and the Last Crusade is a real place! Petra, located in Jordan, is a massive city built into sandstone that was once home to around 10,000 people.

3. Did you know that the Colosseum amphitheater in Rome was built by tens of thousands of slaves around 80 A.D? Located in the heart of ancient Rome, the Colosseum is one of Italy’s most visited tourist attractions.

   It was built by tens of thousands of slaves with stone and concrete.

4. Most of the sites of Chichen Itza are known for their strange sounds. Clapping at one end of the Ball Court will create nine distinct echoes in the center of the court.

5. If you ever visit this Inca wonder Machu Picchu you’ll find that it is made up of over 150 buildings. And to stop the structures from falling down the mountain, the Incans built over 600 terraces!

6. The construction of Taj Mahal took just over 20 years to complete. It also took about 20,000 artisans, as well as a thousand elephants to help with the transport of heavy materials.

7. Christ The Redeemer was covered with around six million stone tiles! The workers who made the tiles would often write on the back – so this statue is covered with secret messages.