On passing through this tunnel and coming out the other side, the environment is very different; it is more humid and green due to moisture from the Caspian Sea, and this abundance of mist and rain is part of the attraction for tourists from the desert zones of Iran.

[12][additional citation(s) needed] Ramsar's Talesh Mahalleh district is the most radioactive inhabited area known on Earth, due to nearby hot springs and building materials originating from around them.

One of the most commonly used models of radiation-induced cancer posits that the risk rises linearly with dose at a rate of 5% per Sv.

[20] If this linear no-threshold model is correct, it should be possible to observe an increased incidence of cancer in Ramsar through careful long-term studies currently[when?]

[21] More recent epidemiological data show a slightly reduced lung cancer rate[22] and non-significantly elevated morbidity, but the small size of the population (only 1800 inhabitants in the highest-irradiated areas) will require a longer monitoring period to draw definitive conclusions.

[25] Pending further study, the potential health risks had moved scientists in 2001–02 to call for relocation of the residents and regulatory control of new construction.

Underground water dissolves radium in uraniferous igneous rock and carries it to the surface through at least nine known hot springs.

Some of the radium precipitates into travertine, a form of limestone, and the rest diffuses into the soil, where it is absorbed by crops and mixes with drinking water.

[29] Signatories meet every three years as the Conference of the Contracting Parties (COP), the first held in Cagliari, Italy, in 1980.

The town also offers hot springs, the green forests of the Alborz Mountains, the vacation palace of the last Shah, and the Hotel Ramsar.