My Map

library(leaflet)
holiday <- data.frame(country = c("Holland", "Spain", "Italy", "Austria", "France"),
                      count = c(3,1,3,18,13),
                      lat = c(52.1326, 40.4637, 41.8719, 47.5162, 46.2276),
                      lng = c(5.2913, 2.2137, 12.5674, 14.5501, 2.2137))
holiday

##   country count     lat     lng
## 1 Holland     3 52.1326  5.2913
## 2   Spain     1 40.4637  2.2137
## 3   Italy     3 41.8719 12.5674
## 4 Austria    18 47.5162 14.5501
## 5  France    13 46.2276  2.2137

holiday %>%
  leaflet() %>%
  addTiles %>%
  addCircles(weight = 75, radius = sqrt(holiday$count) * 30)

## Assuming "lng" and "lat" are longitude and latitude, respectively