library(leaflet)

my_map <- leaflet() %>%
        addTiles()
my_map

Add location of one tourist attraction

my_map <- my_map %>%
        addTiles %>%
            addMarkers(lat=41.4272, lng=-72.4287, popup = 'Gilette Castle')
my_map

Create data frame

set.seed(2018)
CtLatLong <- data.frame(
                lat = c( 41.4272, 41.4916, 41.4745, 41.3543, 41.3733, 41.4850),
                lng = c( -72.4287, -72.0915, -71.9599, -71.9665, -71.9533, -72.3373))
        
CtLatLong %>%
        leaflet() %>%
        addTiles() %>%
        addMarkers()

Add multiple pop-ups

CTSites <- c(
        "<a href='http://www.ct.gov/deep/cwp/view.asp?a=2716&q=325204&deepNav_GID=1650%20'>Gillette Castle</a>",
        "<a href='https://mohegansun.com/'>Mohegan Sun Casino</a>",
        "<a href='https://www.foxwoods.com/default.aspx'>Foxwoods Casino</a>",       
        "<a href='https://www.mysticseaport.org/'>Mystic Seaport</a>",
        "<a href='http://www.mysticaquarium.org/'>Mystic Aquarium</a>",
        "<a href='http://www.ct.gov/deep/cwp/view.asp?a=2716&q=325188&deepNav_GID=1650'>Devils Hopyard</a>"
        )
        
CtLatLong %>%
        leaflet %>%
        addTiles() %>%
        addMarkers(popup = CTSites)