The attack on Monday evening at an Ariana Grande concert in the British city of Manchester killed at least 22 people, including children. It was the worst terror attack to hit the U.K. since the London bombings in July 2005.
Police have identified 22-year-old Salman Abedi as the suspected suicide attacker, but they're still trying to establish if he was part of a wider network.
ISIS claimed responsibility for the attack but offered no evidence of its involvement.
This kind of incident has a big emotional impact on people, making them feel that the world is more dangerous and not welcoming.
Would-be tourists may be seeing this as part of a pattern of bad stuff in Europe and thinking they shouldn't go to Europe.
The Manchester bombing followed a high profile attack in London in March when four people died after a man rammed a car onto a busy sidewalk near the houses of parliament.
Attacks in cities such as Berlin, Brussels, Paris and Nice within the last two years have already made some people wary about traveling in Europe.
French visitor levels dropped 4% in 2016 and spending by travelers slowed. This contributed to the first decline in visitors to Western Europe in many years, at a time when global tourism is growing.
Britain's tourism industry has held up well, however. Overseas visitor numbers to the U.K. rose by 18% in the first three months of 2017 to 8 million.
A weak pound has helped it fell sharply after the Brexit referendum in June 2016 making British hotels, restaurants and shops much cheaper for people exchanging dollars or euros.
Experts say the Manchester attack won't prevent tourism in the U.K. from continuing to grow this year, but it may slow the rate of expansion.
In the wake of Monday's bombing, Euromonitor downgraded its forecast for growth in visitor numbers to 4.9% from 5.1%.
That means it expects roughly 100,000 fewer people to visit the U.K. this year than might otherwise have done so.
In the scheme of things, it's a very small downgrade, said Euromonitor's top travel analyst, Caroline Bremner. But there's obviously going to be an effect.
The U.S. State Department issued a travel alert for Americans visiting Europe earlier this month, citing the continued threat of attacks, particularly in tourist hot spots.
While local governments continue counterterrorism operations, the Department nevertheless remains concerned about the potential for future terrorist attacks.
How the British authorities respond to Monday's attack will be critical since travelers will be looking for reassurance that it is okay to come to the U.K., said Euromonitor's Bremner.
On Tuesday, the U.K. raised its threat level to critical, the highest possible and a signal that intelligence services believe another attack is imminent.
London's Metropolitan Police said they are reviewing all upcoming events in the capital, and armed members of the military have been deployed to guard locations around London.
London is a top draw for international tourists, while Manchester only sees a fraction of the capital's visitors,just over 1 million per year, according to Euromonitor.
We would anticipate that air travel will be somewhat less affected than if it were a world renowned city to visit, noted Olivier Jager, CEO of travel intelligence firm ForwardKeys.
Even so, this second attack on U.K. soil in three months will raise anxiety among some travelers.
Even if there's a small shift in behavior over the long term, it will really add up to a significant financial impact, warned Surry.