Many people can find a doctor close to where they live, but for millions living in rural communities health care is many miles away. To tackle this organizations have found innovative ways of getting hospitals on the move, taking them right to the doorsteps of those in need.
Around 700 rivers are constantly shaping Bangladesh's landscape - building up some areas, flooding others, and moving small sand islands that people call home.
Along these rivers and the low lying coastal regions it often isn't possible to build permanent hospitals.
One charity has turned to these rivers to solve the problem they create.
"The rivers go into the most remote, the poorest, the most unaddressed communities which the roads do not go to," explains Runa Kahn, executive director for the charity Friendship.
"Rivers [are] the best tools by which we can carry our care to the people. Hence, hospital ships."
One of Friendship's floating hospitals brings health care to remote areas of southern Bangladesh.
The ship is a former Greenpeace boat - the Rainbow Warrior II - that has been converted into a hospital to serve the vulnerable coastal region.
It is fully equipped to provide these communities with simple treatments and medicines as well as eye, dental and other surgeries.
Abu Taher is one of the people these hospitals help. He has long-term problems with cataracts.
"I can see only with one eye. I can't walk properly and can't read anything. I can't even go to mosque to offer prayers," he explained.
The ship will allow him to receive free treatment he would not otherwise get.
"There is a government hospital in my village, but they don't offer any eye treatment," he said.
Along with two other ships in northern Bangladesh, this hospital ship helps roughly 155,000 people each year.
Using existing transport options to get hospitals on the move has proved a successful way of meeting the shortfall in health care in rural areas.
One charity has teamed up with the Indian government and railways to convert trains into roving hospitals that use over 75,000 km of India's railways to reach people in the remotest corners of the country.
Like the hospital ships in Bangladesh, the Lifeline Express trains contain, among other facilities, operations rooms, dental and eye units, laboratories and X-ray rooms.
The trains tour the country offering free treatment and cutting edge surgery to India's rural poor. They have provided procedures ranging from cleft lip operations to ear, nose and throat surgeries to millions of people over the 25 years they have been operating.
Their success has been mirrored in other hospital trains in China and in South Africa.
Projects like the Lifeline Express now include teaching facilities, allowing skills and knowledge to be passed on to local doctors and nurses.
But extensive transport infrastructure doesn't exist in every country, so finding new ways to get to rural health care providers is vital.
Orbis, a blindness prevention charity has developed a unique way of reaching remote areas - converting an aeroplane into a fully equipped ophthalmologic teaching hospital.
"We knew that doctors and nurses within developing countries had limited access to professional development and it was extremely expensive to bring them overseas for training opportunities with tuition, travel and accommodation costs high," explains Allan Thompson from Orbis.
"As a result we created our Flying Eye Hospital to take the training to them."
Bespoke modifications inside the plane means that it now houses facilities including classrooms, operating theatres and laser rooms.
Here, local doctors and surgeons can watch live surgeries and be taught new techniques and skills by staff and volunteer doctors.
"The plane has helped to conduct training in all areas of ophthalmology, from cataract, to glaucoma, to oculoplastic, to laser services across 92 countries," Mr Thompson said.
These services change the life of people in rural communities - allowing them to work and live more easily.
Back in Bangladesh, Mr Taher is recovering from his cataract surgery on the floating hospital.
"I'm feeling good after cataract surgery," he says. "It was a smooth operation.
"Now I think I'd be able to regain my vision. I feel like I've got a second life. This hospital came to us as a blessing."