Making sure you have the right visa can be one of the biggest hassles of travelling abroad, so we're bringing you a series of bitesized guides to some of the more complicated travel regulations - including the Western Hemisphere Travel Initiative (WHTI) and the USA's Electronic System for Travel Authorization (ESTA).

First up is Europe's Schengen Visa.

What is it?

The Schengen Visa enables holders to travel between its 15 European member countries on a single visa. The holder can travel to any or all member countries. First signed in 1985, the Schengen Agreement was designed to open up Europe's borders, making it easier to travel between countries on the continent. Internal border controls between the member countries have stopped - making it similar to travelling from one US state to another. All internal air, road and train trips are handled as domestic travel. Schengen Visas are for leisure, tourism or business visits.

Who is it for?

People who want to visit several European countries on the same trip, who are required to obtain a visa before entering Europe. Schengen Visas are also available as airport transit visas and transit visas - for passengers who will be passing through the Schengen Space.

Where can you go?

The Schengen Visa is currently available for travel between the following countries: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Italy, Luxembourg, Norway, Portugal, Spain, Sweden and The Netherlands. Travel between these countries is not subject to any stops in order to check passports.

A total of 30 countries have signed the agreement, but only 15 have implemented the common border control and visa provisions.

In 2008, Hungary, Poland, Czech Republic, Slovakia, Estonia, Lithuania, Latvia, Malta and Slovenia joined the Schengen Space - allowing them to stop border controls at both ports and airports.

How much does it cost?

Most embassies and consulates charge €60 for a Schengen Visa.

Validity

A Schengen Visa allows the holder to travel within the Schengen countries for a maximum stay of 90 days in a six month period.

How to apply

Applications for Schengen Visas should be lodged at the relevant embassy or consulate in your country of residence. If you plan to visit one Schengen country, you should apply for a visa at the embassy or consulate of that country. If you're visiting several countries, you should apply to the embassy or consulate of your main destination (if you don't have a main destination, apply to the embassy or consulate of your first port of entry).

Working days required

Visa processing will vary, sometimes dependent on nationality. They can take anywhere from one day to 10 weeks.

Did you know?

The name Schengen originates from the small town in Luxembourg where the agreement was first signed.

Don't forget to check back next week for our bitesized guide to the ESTA.

Visa and passport information is updated regularly and is correct at the time of publishing. You should verify critical travel information independently with the relevant embassy before you travel.